Discuss IDEAL ICOS HE24 - losing pressure after heating is turned off in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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cullia

Hello,

I am new to the forum so hello to you all and here's hoping someone can help pin point what our issue is? I have some knowledge of our system from researching the internet.

We have a three storey house. On the first floor is an Ideal Icos HE24 boiler. On the third floor is a Megaflow CL250 hot water tank. Alongside the hot water tank is the red expansion vessel, sitting off the expansion vessel is the PRV and the pressure gauge along with the filling loop.

Our hot water and heating works fine. The boiler was noisy when the heating was on but that was down to the fan and we have had that replaced.

Now, when the heating ISN'T on, the pressure is maintained. We can have showers, put the washing machine on, dish washer on and the pressure stays constant. However, when we turn the heating on, the pressure goes up by about 1.5 bar to 2.5 bar and we noticed water was being expelled out the overflow pipe from the PRV. When the heating is then turned off, within 24 hours, the pressure drops to zero. Despite the pressure dropping to zero, the boiler still works and heating and hot water is available.

On the first engineer visit, the expansion vessel turned out to be flat and needed re pressurising. This would explain the water coming out the overflow. It also looks like we were putting too much pressure into the system when it reached zero. After pumping up the expansion vessel, the system pressure still dropped to zero. On the second visit, the same engineer said the expansion vessel was still pumped up and then replaced the PRV. The system pressure still dropped to zero. On the third engineer visit, the expansion vessel was flat again. This time he put an extension valve on the pressure release valve, an extension that allows the expansion vessel to be pumped up when you cannot access the valve. The engineer thought the valve was leaking on the expansion vessel and so this extension valve is effectively a new valve and would stop the original valve leaking. Since fitting the extension valve, the system is still losing pressure. There is no water coming from the overflow pipe anymore as I tied a plastic bag to the end of the pipe to capture any water and there was no water in the bag. After the third visit, the engineer concluded that if after replacing the PRV and attaching a new valve to the expansion vessel, the only other thing it could be is a leak within the pipework. There was no suggestion of checking the boiler for leaks. I have had the heating on for 50 minutes and checked every radiator for leaks and there aren't any. I mentioned to the 3rd engineer whether it could be the heat exchanger on the boiler and he said it would be extremely hard to prove but it is possible. He basically said that if there is a leak in the pipework, they could use a gel to put in the system and to seal the leak if it is an inaccessible leak. There was no suggestion of checking the boiler for leaks and I will not be allowing them to mask the problem with leak sealer without checking the boiler. From what I have read, a heat exchanger on this boiler would cost £400+ to replace and they may be trying to avoid replacing this in favour of a £16 bottle of leak sealer. What are your thoughts on this please people and what in your opinion should be looked at next to rule out leaks in the pipework? I should mention the house is 10 years old\timber frame and the pipework for the rads is plastic and feeds into the cavity walls rather than on the surface of the walls as with older houses with copper piping.
 
Welcome to the forum.

You can easily prove whether it's the boiler or your pipework. Under your boiler are two valves, one on the flow, one on the return.

While the system is cold, top up the system pressure as normal. Make sure the boiler is turned off then turn these valves off

2016-08-11 23.00.30.png

If the pressure drops on the gauge it's your boiler, if it holds its pressure it's your pipework.
 
just a note be warned the iso valves might leak once moved/turned
 
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