What a Bad Solar Pool Heating Install Looks Like

Solar pool heating is simple in principle. Water is pumped up to collectors on your roof, the sun’s heat is transferred to the water, and it flows back into the pool a few degrees warmer. Do that for enough hours across the season and you get a warm pool for almost no running cost. 

The catch is that almost all of the performance, and almost all of the problems, come down to how the system is sold or installed. The same collectors on the same roof can either quietly and economically heat your pool for fifteen years plus (some systems even 30 + years!) or leak and underperform inside a couple of seasons, primarily depending on the workmanship and whether it was installed to the manufacturer’s specification and the Australian Standard for solar heating of swimming pools (AS 3634:2022). 

So, this is not a piece about who to blame. The majority of installers do an excellent, if not incredible job. It is a piece about what a good install actually looks like, what can go wrong when corners get cut, and the handful of things any pool owner can look at or ask about to check their own system. If your new solar is not performing, or you just want peace of mind that it was done properly, this is what to look for. 

For the record, genuine manufacturing faults do happen, and when they do, they are covered. But across the systems we are asked to inspect, the overwhelming majority of problems trace back to how the system was sold or installed, not the system itself. That is the honest pattern, and it is why the checks below are worth your time. 

We also must note that there are instances where none of the above are applicable and it is important to know that external or environmental causes can come into play such as wildlife including cockatoos, hail, humans (yes humans), and other similar causes. 

Water has to be able to drain back out

When the pump stops, the water in the collectors should drain back down out of the panels. A correctly designed system does this on its own through the way the plumbing is set up. The installation manuals are specific about how this is plumbed for exactly this reason. Now, we know that not all systems can be done this way, in which case we cover mitigation tips later in this section. 

If your system cannot automatically drain, it leaves the collectors sitting full of water whenever the system is off. A system that stays permanently flooded carries problems. In colder areas, water left in the collectors can freeze and split rigid panels. And for flexible? Well frost isn’t an issue for this type of system however, during hotter periods when the pump turns off, water sitting in the collector with no flow to carry heat away lets it stagnate and overheat, which introduces the risk of bursting the tubes when the pump starts, caused by hydraulic hammering (rigid panels can handle much higher pressures and temperatures). None of this shows up immediately, which is part of why it gets missed. 

This is not theoretical. On one hot-climate roof we inspected, a flexible system had burst along the crests of the roof profile: classic stagnant water with nowhere to drain. The rectification was straightforward: repair the burst section, confirm the controller’s anti-boil was actually enabled and working, and the elephant in the room — reduce the over pressurisation of the system as it had a massive dedicated 280LPM pump, significantly bigger than it should have. 

On the frost side of things (and note this is a rigid-panel only) we have pulled apart all sorts of rigid panels that had frost-split for one reason only: the system stayed flooded and could not drain before a frost hit. This is not limited to obviously cold regions either; any frost-prone area can do it, and even milder areas can throw up the odd cold anomaly. 

To mitigate or even eliminate this risk, it is important to winterise your rigid panel system by manually draining them via valve or lifting the panel to drain the water. Adding a controller with Anti-Freeze can help but should not be considered a permanent solution, as it requires 100% uptime during winter. 

For flexible systems, ensure your system pressure is within acceptable limits (Boss specifies 100kPa max for bottom-fed systems (automatic draining) and 50kPa for flooded systems (cannot drain)). Utilising a controller with Anti-Boil can help but should not be considered a permanent solution, as it requires 100% uptime during the hotter months. 

The best option for either? Where possible, design the system so it can automatically drain or, for existing systems, re-plumb the system so it can. 

What the Standard requires

Under AS 3634:2022, a solar heating system must be designed to drain down when the circulating pump stops, so that only a minimal amount of high-temperature water is returned to the pool on start-up. 

It also requires the control system to keep pool users from ever being exposed to water hotter than 40°C. 

In other words, drain-down is not a nice-to-have that a good installer adds; the Standard treats it as core to the design. Where a roof genuinely cannot gravity-drain (commonly found on parapet and inverted-slope roofs where it is physically impossible without cutting through the structure), that is exactly when the mitigation above (pressure limits, winterising, anti-boil/anti-freeze) becomes essential, and your installer should have raised it with you before the job started. 

What you can check: this one is difficult to judge from the ground, so it is mostly a question to ask. Get your installer to confirm in writing whether the system drains down when the pump stops, and if it cannot, that it is compliant at the pressure and flow it runs at, what winterising or controller protection it needs, and specific maintenance requirements for your system. 

Flow has to be balanced across the whole array

This is the one that quietly robs performance, because the system still runs, it just does not heat the way it should. 

Collectors are made up of many tubes, and the water will always take the path of least resistance. A properly designed array is plumbed so that every collector sees roughly the same flow, which usually means feeding the water in a way that all the flow paths are a similar length. Done right, water fills evenly across the whole array and every collector sees even heating across the system. 

Done wrong, with the feed and return at the wrong points, no balancing and/or multiple arrays not balanced for even flow, the water cuts through the nearest, easiest path and essentially bypasses the collectors furthest from the flow. The bypassed sections barely contribute, so a system that looks the right size on paper behaves like a much smaller one. You paid for the whole array and you are only really using part of it. It can also run hotter in the starved sections, because there is not enough flow through them to carry the heat away. 

What you can check: using the back of your hand you can feel for hot spots across the collector, use pressure gauges to check the system is balanced, or arrange for a Boss installation partner to conduct a site visit and system health check, even if it isn’t one of ours. Boss installation partners are experienced in solar pool heating and many of the fundamentals carry over to other systems. Flow balance is one of the first things worth having looked at when a system is underperforming. 

The manifolds and joins have to allow for movement

Two things matter here: they have to be assembled to the manual, and they have to be free to move. 

Manifolds expand and contract a lot with temperature. A long run of manifolds can move tens of millimetres between a cold morning and a hot afternoon, or up to 90mm for Rhino panels. The manual accounts for this by specifying how the manifolds are trimmed and joined and how the fixings are spaced, with the fixings deliberately not clamped down hard so the system can move. When manifolds do not have expansion and contraction accounted for, or a clamp is done up tight against a fitting, that movement has nowhere to go. The force does not disappear, it gets taken out on the weakest point, typically the joins, and over time this appears as buckling and cracking at the manifolds or pipework. 

To put a real number on it, we calculated on a customer’s system that had issues: a Tufman Premium manifold system that is 8.8-metre long will move close to 60mm between a cold winter morning and a hot summer afternoon. If a clip or clamp is done up hard against a fitting, that force has to go somewhere, and we have observed systems where the manifold system buckled in the middle section, causing stress damage. The Boss manual is specific here: fixings should sit with a gap of less than 100cm between clips, and they must not be done up so tight that they stop thermal movement. For Rhino systems the area to watch for is that PVC and PP are different materials and move at different rates. Using Rhino flexible couplers each end of the system and/or for long pipe runs, creating expansion zones within your pipework allows for expansion and contraction, as we have seen PVC fittings distorted and cracked due to this. 

The other common manifold killer is gluing (flexible systems only). Too much glue, the wrong glue, or glue applied to the female part of the coupling creates a bead of adhesive inside the joint, and that becomes a stress point that cracks open later. It has a name, solvent stress cracking, and it is not a manufacturing fault; it is a fitting fault. We have seen it on both DIY assemblies and trade installs. It is covered in the manual and stamped as a warning right on the manifolds themselves, which is worth remembering if a repairer tells you a cracked header is a product defect. 

For flexible systems requiring long manifold runs, we recommend either breaking the run up or using a Tufman flexible joiner to provide movement relief. 

For panel systems, ensure Rhino flexible couplers are used at each end of the system, and for long pipe runs, creating expansion zones within your pipework allows expansion and contraction without damaging fittings. 

What you can check: visually check your system against the Boss manual, and check that pipework and manifolds have room to move and are not fixed down hard with nowhere to go. 

Poor Heating Performance? It has to actually be big enough

The Australian Standard sets a minimum collector area as a proportion of your pool’s surface, and that number has been set since the 80s. Be aware that it varies with where you live and typically speaking that the required pool to collector area is 80 percent to 100 percent of the pool surface in the cooler southern states and down to 60 percent to 80 percent north of the Capricorn, but the point is that there is a floor, and sizing below it leaves the pool short of heat. 

This one matters most when a system is being replaced. In one job we were involved in, the customer had been sold and paid for 40m² of collector, but only around 32m² was physically installed and it was priced as a “system replacement” with no actual coverage disclosed. Our Boss installation partner went out, inspected the system, and added Boss Rhino panels to the existing (competitor’s) system to bring it up to the coverage the customer had paid for, turning a short-changed job into a happy customer (with Boss at least…) 

Less collector area simply means less heat captured, which means a cooler pool and a shorter swimming season, no matter how neatly it is installed. There is no replacement for coverage, that is pure physics and you cannot bend science. Even our market-leading Nano collectors are not exempt from the Australian Standard, and their performance gains are measured on a 1:1 square metre ratio so they still fall under the same coverage amounts outlined in the standard. 

One caveat to the above: if you simply do not have the roof space available, then yes, install the largest system you can, anything is better than nothing. And if a system is underperforming, it may well be undersized, but adding more collector before checking what is actually causing the shortfall can be a band-aid fix, so get it properly assessed first. 

What you can check: if you are replacing an existing system, get the collector area of the old system and the quoted area of the new one, in square metres, and make sure the replacement is genuinely like for like. A good installer will disclose the system size in square metres and provide the coverage percentage. 

The short version, before you sign or after you worry

You do not need to be a tradesperson to sanity-check a solar pool heating install. Working from the ground and from a couple of straight questions, you can cover most of it: 

• The collectors sit flat and neat and the U-loop ends are stuck down with silicone. 

• Flow and pressure have been adjusted to suit your system and are operating within safe limits. 

• For reverse-return flexible systems, a balance pipe is always installed (there are very specific designs that may omit this, but in practice they are rare and if you are unsure you can always check with Boss). 

• The system is designed to drain back down when the pump stops, and if not, the installer has checked, verified and advised you of the system pressure and flow, and that it is compliant. 

• Rigid systems have the ability to automatically drain in frost-prone areas (water can freeze in collectors at ambient roof temperatures above 0°C). 

• The array(s) balance so all the collectors are equal in flow. 

• Fixings are not clamped hard against fittings. 

• The collector area meets the Standard for your pool, and matches what you had if it is a replacement. 

• Systems are mounted in a way that does not impede the natural flow of your roofing profile (e.g. NOT placed in valleys of Kliplok or overlapping on tiles). 

If most of those check out, you very likely have a sound install. If several do not, it is worth getting an independent set of eyes on it before a small fault becomes an expensive one. 

It is highly recommended to have yearly inspections or maintenance on your solar system. This keeps your system healthy and in tip-top shape, with the benefit of catching anything that might surprise you once the season is in full swing, and while you’re there, we highly recommend checking all of your pool equipment. You’ll thank us later! 

Frequently Asked Questions

How do I know if my solar pool heating was installed correctly?

Most of it you can check yourself. The system should be designed to drain back down when the pump switches off, and there should be no cracks or leaks at the manifolds. The array also has to be sized to the Australian Standard for your pool, which is broadly 80 percent or more of the pool’s surface area in southern states. If it is heating unevenly or underperforming for its size, the flow balance across the collectors is worth having checked. When several of these are off, get an independent inspection, or if you are ever unsure, send us an email with photos and we can remotely assess your installation. 

Can a badly installed solar system still be fixed? 

Often yes. Many faults (poor mounting, a clamp done up too tight, or flow that is not balanced) can be corrected without replacing the whole system, as long as the collectors themselves have not been damaged. The starting point is an honest inspection against the manufacturer’s specification and the Australian Standard, so you know which parts are sound and which need to be re-done. What cannot be fixed cheaply is an undersized array, because that comes down to how much collector is on the roof. 

What does the warranty actually cover?

Boss backs its systems with a long warranty when installed correctly with all the components set out in the manual(s). The best way to protect that cover is simple: make sure the system is installed to the manufacturer’s specification from day one. Get that right, and a good solar system will quietly pay you back season after season for years to come. 

If you are not sure your system was installed right, or a new one is not performing the way you were promised, an independent inspection is worth it. A compliant installer works to the manufacturer’s specification and to AS 3634:2022, and can walk you through how your system is mounted, drained, balanced, and sized. If yours cannot, that in itself tells you something. 

Figures and observations in this article come from Boss Pool Heating inspections and modelling, accurate at the time of writing (July 2026). Every installation differs, so treat this as general guidance, not a substitute for a site inspection.