Quotes for a New Gas Combi Boiler Installation

Leodogger

Jeepers_Creepers said:

Leodogger said:

I am now having doubts that the plumber we had was as good as he made out.   Last night the heating was on full blast, rads too hot to touch and when we inspected the readings on the boiler, the water temp and rad temp had been turned up to full, despite me telling him that the previous owners had left instructions not to wang the heating up to full (they even put markings on the dial to stay between) because it would cause the pressure to increase too high on the bar readin.   So the water pressure on the "bar setting" which we read in our boiler guidance, should be between 1.0 and 1.5, was in the red which is supposed to be dangerous, or so we were told by a previous engineer.    My husband attempted to relieve the pressure on the tap and the boiler started banging so we had to turn the heating off altogether.    We have now turned the water temps on the Central Heating down to where it was previously and left the water temperature almost as high as the plumber put it and the bar reading has dropped back down to 1.0

What I want to know is, did the plumber really know what he was doing ??? 

I don't know why he turned these controls up to max, unless it was as part of checking the system. Perhaps he just forgot to turn them back down?

This shouldn't be 'dangerous' - there might well be times you'll want these at max, such as in a very cold winter - and this shouldn't become dangerous, or else the boiler instructions would warn against this...

The fact your system pressure increased when doing this suggests a different issue, like the expansion vessel isn't doing its job as well as it should. But, again, not 'dangerous' (or shouldn't be). The answer is to turn the controls back down... You've done this. Cool.

When the pressure gauge goes into the 'red', it means 'it's too high, man', but not actually 'danger'. It only becomes a problem if it approaches 3 bar, whereupon this opens a safety valve. What did yours get to?

(The previous owner advised against turning it up too high for this reason. That doesn't make him more qualified than your plumber, just that he found out what happens when you do turn it up too high - that's all...)

Anyhoo, I think you are essentially back to your starting point - a semi-dodgy boiler that'll likely keep chugging along, but which will need replacing in the not too distant future. So, do your research and get at least two new GasSafes out to quote.

Consider Viessmann as well as other makes.

Didn't know the boiler had a safety valve.    Asked my husband what it got up to and he said "3", it was actually sitting in the Red Zone which is what worried us.    It just means we can't have the heating hot enough but that puts us back to square one how it was before, but why didn't the plumber comment on the controls being turned down before he told us the system might want flushing and draining down.  Shouldn't he just have turned the controls up to start with and told us that the heat exchanger is probably not working up to scratch when the pressure increased too much?    I did tell him that the previous owners told us not to put the CH on the highest setting because it affected the pressure in the system too much, or perhaps he didn't think it was important if the pressure got too high.   He never said what to do if it did get too high.

Ectophile

If the pressure gauge goes into the red when the heating is on, it means that the expansion vessel has failed.  It's quite common.  The short-term "fix" is to turn the heating down so that the pressure doesn't rise so high.  The proper fix is to replace the vessel.

Be aware that pressure relief valves can stick.  Usually, they stick open and the pressure keeps dropping to zero.  But I once had one that stuck closed.

If it's a condensing boiler, then it's more efficient with the temperature turned down.  A boiler ticking over on low power for several hours is more efficient than one running at full blast for a shorter period.

Leodogger

Ectophile said:

If the pressure gauge goes into the red when the heating is on, it means that the expansion vessel has failed.  It's quite common.  The short-term "fix" is to turn the heating down so that the pressure doesn't rise so high.  The proper fix is to replace the vessel.

Be aware that pressure relief valves can stick.  Usually, they stick open and the pressure keeps dropping to zero.  But I once had one that stuck closed.

If it's a condensing boiler, then it's more efficient with the temperature turned down.  A boiler ticking over on low power for several hours is more efficient than one running at full blast for a shorter period.

It is a condensing boiler but again our plumber never told us that it was better to leave it ticking over on low power because it is more efficient, he just wanged them both up to high !