Heating engineer advice - Ideal Logic combi - isolated heating and pressure issues.

Please would any heating experts advise what damage the heating engineer could have caused to our boiler. He isolated the boiler, turning off valves to the heating so that he could decide whether the ongoing pressure drop (0.5 bar a week drop) was within the boiler itself, or whether a pipe in the heating system has a leak. He had previously recharged expansion vessel, said pressure valve is dry, and said heat exchanger 'looks' okay.

Trouble is he left the hot water working after the valves were isolated, and told us we could keep using hot water. Within a few hours the pressure was at zero. The water kept working afterwards and the engineer came back to tell us that the gauge had gone over the top because the hot water had caused the pressure in the boiler to rise too high. (Nowhere to put the excess heat from HW as the central heating was isolated). Apparently the hot water shouldn't be used in this situation on our boiler. We had used the HW for 5 days while isolated. My query is - what harm will this have caused the boiler apart from it needing a new pressure gauge on.

Water and heating are now both off for another 4 days, boiler is isolated with red tape on it saying do not use, until he comes back to see whether the pressure in the boiler drops again. (He has fitted a new gauge and repressurised the isolated boiler to 2). What problems might this have now caused by the hot water overheating to the extent that the gauge went over the top and broke... in case he says we now have more faulty parts in addition to pressure dropping. Knowledgeable advice greatly appreciated. Thank you. Jan

Unable to directly answer the question however considering the amount of time where you`ve been without heating or water I would get another engineer in

rpm said:

Unable to directly answer the question however considering the amount of time where you`ve been without heating or water I would get another engineer in

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Thank you for your reply, I should have mentioned it's a British Gas homecare repair with an excess for each separate issue and so I'm keen to understand what issues using hot water whilst heating was isolated might have caused so that I'm not charged for repairing them. Cheers Jan

Jan Chaplin said:

Thank you for your reply, I should have mentioned it's a British Gas homecare repair with an excess for each separate issue and so I'm keen to understand what issues using hot water whilst heating was isolated might have caused so that I'm not charged for repairing them. Cheers Jan

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It shouldn't have caused any major issue as the prv should have opened to remove excess pressure, possibly the prv may need replacing if it hasn't re-seated properly. I would complain to British gas though and ask for a different enginner as leaving you for so long without heating and hot water is unnecessary. If the boiler was leaking internally based on the pressure loss you have been having, isolating the boiler would show pressure loss within 24 hours. Also the enginner could have done a pretty simple check to tell whether the exchanger was leaking internally or not.

As above the boiler should turn off before anything can get damaged.
A 24 hour test should be plenty.
You can get a one off repair from ideal for about £300 assuming it is the boiler at fault

Funding small leaks on pressurised heating systems is a nightmare. They usually evapourate before becoming noticeable. it is correct procedure to isolate boiler from system to give an indication.
Top Up Mate from Flowflex is a good way to stay warm and seek out the leak. Rob Foster
aka centralheatking

Craig Watson said:

It shouldn't have caused any major issue as the prv should have opened to remove excess pressure, possibly the prv may need replacing if it hasn't re-seated properly. I would complain to British gas though and ask for a different enginner as leaving you for so long without heating and hot water is unnecessary. If the boiler was leaking internally based on the pressure loss you have been having, isolating the boiler would show pressure loss within 24 hours. Also the enginner could have done a pretty simple check to tell whether the exchanger was leaking internally or not.

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Thank you for your expertise. A new heat exchanger has gone on today. This puzzles me as there was no pressure drop at all while theboiler was isolated for the last 3 days?? Does the exchanger only cause a drop when the boiler is fired up if they're is a micro leak in that part?? Thank you again for your sound advice about this. Jan

Thats bonkers, before I say something stupid. Where is your pressure gauge located?

Presuming your gauge is on the face of the boiler like I think it is, if you've had no pressure loss then you clearly don't have an issue with the internals of your boiler.

Thank you, youre right the gauge is on the front and pressure dropped 1/10 of a bar on the day it was isolated then no more in the following 3 days. Was the heat exchanger unnecessary. Fitting it seems to contradict what he said. Thanks again Jan

Jan Chaplin said:

Thank you, youre right the gauge is on the front and pressure dropped 1/10 of a bar on the day it was isolated then no more in the following 3 days. Was the heat exchanger unnecessary. Fitting it seems to contradict what he said. Thanks again Jan

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boiler might well be ok
look at top up mate from flowflex ..Rob Foster

It sounds like they're just throwing parts as it until it works. I can't say for certain but based on what you've said, I wouldn't be surprised if your back on here in a couple of days still getting pressure loss.

Craig Watson said:

It sounds like they're just throwing parts as it until it works. I can't say for certain but based on what you've said, I wouldn't be surprised if your back on here in a couple of days still getting pressure loss.

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thats the modern ..not my way..keep throwing parts
uck ...centralheatking

Craig Watson said:

It sounds like they're just throwing parts as it until it works. I can't say for certain but based on what you've said, I wouldn't be surprised if your back on here in a couple of days still getting pressure loss.

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Thank you, it's making an awful rattling noise now too. I'm clear with your help that it's a leak in the system if the pressure falls again. I think I'll try my insurer about track and trace. Cheers for your expertise.

Jan Chaplin said:

Thank you, it's making an awful rattling noise now too. I'm clear with your help that it's a leak in the system if the pressure falls again. I think I'll try my insurer about track and trace. Cheers for your expertise.

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Jan Chaplin said:

Thank you, it's making an awful rattling noise now too. I'm clear with your help that it's a leak in the system if the pressure falls again. I think I'll try my insurer about track and trace. Cheers for your expertise.

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If it's rattling then something could be loose, it may just be he hasn't secured the case properly but if it wasn't doing it before and it is now, call them back to check everything over.