Welcome to the Red Circle Solar trouble shooting page.

Warning! Please read and understand the manual for your specific system before doing any trouble shooting and where required, always use a licensed technician. 


This website page is designed to make the process of working out the issues you are having as quickly and effectively as possible.  Once you have read through the information below and refined what your issue is, please fill out the appropriate form and press submit. The form will be emailed to us. We will then contact you with further information which may include a quote or warranty form along with our proposed  solution to rectify the problem with your system.

Please note: Red Circle Solar does not cover warranties for the following systems although serviceable parts for most models are in stock at red circle solar and available for sale.  Solar Rex. Ultimate Solar. Sunergy. Greenline Engineering.

Please follow the links/prompts below to start the process.

What system do you have?

(Please click on the picture of the type of system you have.)


Tank only no background.jpg

UHE close coupled systems trouble shooting.


Ok, so you have a close coupled low pressure system with a high pressure heat exchange coil. Now please choose from the options below and click on the most relevant button.  


No hot water

Not getting hot water out of your Red Circle Solar hot water system is most likely caused by one of 3 things:

The tank is not full. First off, it is important to manually fill the tank to ensure tank is not dripping/leaking. Once the tank is full, it is important to test the fill kit. Click the button below to see how to test your fill kit.

The element is not functioning adequately -  If you've been getting hot water in the summer months, but not after a few overcast days then your element could need adjusting or may not be working. Firstly check the temperature setting on your thermostat, if this is below 60 degrees, then this could be the reason for a lack of hot water. If the element is already above this temperature, please organise for an electrician to check that the element is working. See testing the element (link in currently under construction)

Wood fire/Wetback not putting heat into the tank - you may have the wood fire on, but are not getting a hot tank. This could be an issue with the flow and return lines, or an issue with the hydronic circuit (see point 4 below).

Plumbing - Often there is no issue at all with the hot water service, but there is an issue with the plumbing after the hot water has left the hot water service. Firstly there is the tempering valve - this mixes hot and cold water together, this could be faulty, or the filters could need cleaning. Secondly, there could be cross over - this is where a mixer tap could be letting cold water enter the hot water pipes. In a similar way, hydronic circuits can strip heat from the tank by taking heat that you want to stay in the tank, this could be due to a faulty pump/controller or a badly designed system.

The best ways to test these items above is by systematically taking temperature readings at various points in the system to determine where the issue could be. For example, measuring the temperature of the water in the tank, then the temperature of the hot water (pipe temperature) coming out of the tank, then the temperature of the tempered water (pipe temperature) after the tempering valve - This would indicate whether the tempering valve is working correctly for example. In some more complicated scenarios, you may also need to take some temperature readings at a couple of points in the day to determine exactly what is going on.


Tank is overflowing

When your hot water system is first commissioned it will be fuller than it would be under normal operation. As the cold water in the tank heats up, it will expand, and will overflow slowly. This will correct itself, but you may notice it takes a couple of days to find the correct level (depending on the time of year).  If the tank is overflowing more than this, then please have the following checked.

The fill kit (this keeps the tank full of water).

Start off by covering the small solar panel on the top of the hot water system. If this stops the flow, there is an issue with the fill kit. If the tank is still overflowing, please check the fill line (this squirts water from the solenoid valve into the tank, removing this line from the solenoid will let you know if the overflowing water is coming from the solenoid.

If either of the above stop the tank overflowing, then there is an issue with the fill kit. Please see the fill kit troubleshooting guide by clicking the button below.

Mains pressure source - If the water is not coming from the fill kit, then it must be coming from the mains pressure side of the system. There are a couple of sources where the water could be getting into the low pressure body of water in the tank.

(1) Leaking coil fittings - there are no joins inside the tank to leak, the coil actually comes out of the top of tank at each end, and plumbing fittings connect onto the coil. Most of the time, what looks like a leaking coil is actually a loose fitting, or a wrong connection.

(2) Leaking coil - while this is rare, we have seen leaking coils in the past. If it's not the coil fittings, then it's time to drain the tank, remove some tubes and look/listen inside for a leaking coil. You may start at one end, and hear that the leak is down the other end. Remove more tubes until you can see the leak, and get photo's of the leaking coil, you will need this as part of the warranty process. Please click the button below to go to the warranty page:


Tank is dripping/leaking

A few drips from your hot water system could be just condensation from the night before, there will often be a few drops of moisture underneith a tank. If it's more than this it could be one of a few things:

Split seal - If the leak is mainly localised to a tube/tubes, it may well be an issue with the internal white silicon seals. You should have got a spare seal with the tank. But if you do need to order new seals, it's best to order more seals than you think you need to replace, as they can sometimes fall into the tank during installation.


To replace a seal, (1) Drain the tank. (2) Carefully remove the glass tube (see manual for handling instructions), and remove the two neighbouring tubes as the water could be coming from one of them. (3) Visually check that the seals, and feel them with your fingers. If you find a damaged or badly seated seal, remove it by hand. If there is insulation pushing the seal out of shape, cut this back. (4) Get a new seal (the bevelled inner edge facing out, for the tube to slide into). (5) Place the seal around three fingers, then work seal into the grove in the inner tank, as soon as part of the seal clicks into place, work the pressure around the rest of the seal. (6) Visually inspect seal, it should look perfectly round in the tank. (7) Lubricate and re-insert the tubes (see manual link)

Over filled - If the water seems to be coming from the top of the tank, please check the water level in the tank. The water level in the tank should be 110mm down from the top of the vent fitting in the centre of the tank.  If the tank is too full, then it will overflow. Please see overflowing

Dripping valve - The cold water expansion valve (CWE) will drip regularly to allow the water in the coil to expand when a hot tap is turned off. If it is dripping more frequently than this, it could be a faulty CWE valve, or it could be that the water pressure is higher than what the valve is rated for. Check that all the valves are correct as per the installation manual

Issue with tank - Hopefully you do not have an issue with your tank. If you suspect a leak from the tank, you can do one of 2 things (1) Isolate the tank for 24 hours to see where the water level is when the leak stops, this will give us an idea of where the leak is coming from. (2) Remove tubes from a few spots in the tank, to have a look inside with a torch, if there is an issue with the inner tank, this should be easy to see through the tube holes using a torch. If there is an issue with the inner tank, please go to our warranty section  as the tank may need to be replaced.



Ok, so you need some spare silicon seals. Please fill out the form below. (remember, 2 is 1. IE, order 1 or 2 extras just in case)

Name *
Please advise if the number of seals required is not below.

There is boiling/excessive venting

As with any brand of low pressure hot water system, you can use a variety of heat inputs, but there is no way of stopping the heat going to the tank when the tank is hot enough. If heat keeps going into the body of water, then the tank will eventually boil.

Installation effects - Now while boiling is fairly common in summer months, it should not be a particularly dramatic event. Due to the roof materials of some houses, and their structural design, the boiling of some systems will be more noticable than others. There are some installation factors below that will impact the way a system boils or vents steam:

(1) The angle -  The vent on top of the system needs to be pointing directly upwards when viewed from the end of the tank. Imagine the end of the tank is a clock face, the vent needs to be as near to 12'o'clock as possible. If the tank is leaning too far back or forward, there will no longer be a sufficient air gap between the body of water and the base of the vent, and as a result water will be ejected from the vent upon boiling.

(2) Rubber tiles - This really effects the noise of the boiling tank. Installers often use small rubber tiles between the metal frame and a metal roof for example. The rubber will absorb a lot of vibrations and therefore sound.

(3) Wood fire - If your woodfire has a high kW rating for the wetback/flue jacket, then your tank will heat up very very quickly in winter. Similarly, a lower kW rating on a fire than is on for pretty much the whole of winter will often provide more hot water than you'll need.


Depending on the scenario above, we have some suggestions below to minimise the effects of boiling/venting

(1) Correct the installation - Get the tank installed at the correct angle for your roof. See Installation Manual.

(2) Limit solar gain - less solar gain means less heat in the tank in the summer months. Some people will use a shade sail, which essentially covers up 50% of the surface area of the tubes with  90% UV block shade cloth. This can be wound up/down as required. A lot of customers leave it up all year round. Another option, is to turn a few of the evacuated tubes around, some times turning 6 tubes around on a 30 tube system makes a huge difference to overheating which still providing lots of free hot water. Click here to buy a shade sail (They are $130 including postage)

(3) Use more hot water - this can be achieved in a number of ways, for a standard installation it could be doing hot washes or a hot feed to a dishwasher (where possible). For customers with hydronic heating, a well designed system with good controls will provide a lot of heating throughout the house, and will stop the tank from ever getting above 80 degrees during the winter. Combining this with solution (2) will eliminate boiling all year.

(4) Limit woodfire gain - If the woodfire is providing more heat than is necassary, then there are ways to limit the efficiency of the wetback, for example using fire bricks.


Something else

We have tried to cover most trouble shooting above. If it is something else. Please contact us on this form and we will get back to you. Or if it is urgent please give us a call.

Name *
Please explain clearly how we can help you. As much information as possible will help us address your issue effectively and quickly.
So we understand that your having trouble working out why your UHE close coupled system is not working as it should. Please tick the box's that apply to you.