New boiler disaster

thedr

I like the idea of an independent expert coming in to assess the suitability of the boiler. Should I just get in another boiler installer to do this?

pinkshoes

thedr wrote: »

I like the idea of an independent expert coming in to assess the suitability of the boiler. Should I just get in another boiler installer to do this?

You need someone qualified with a good reputation, that is willing to put in writing on headed note paper what is wrong with the boiler.

This is required should you have to take the original fitter to court to have the boiler changed.

unclebulgaria

Hmm and when the said qualified engineer writes that there is actually nothing wrong with the combi other than the installer didn't really explain things properly and he's fitted an isolation valve to limit the incoming mains water flow, what then?
The incoming gas pressure should be ok as I'd expect the Gas Safe inspection to have shown up incorrect gas supply pipe sizing so its a fair bet its not under gassed.
The boilers operation should be ok for the same reason above.
It's probable that the installer decided that due to the size of your flat and your water requirements anything bigger than 24kw was too big and possibly a false economy. Personally I won't fit a 24kw unit unless the customer has completely understood what it will provide.
Find a vessel that you can measure the quantity of water in and time how long it takes to fill when the cold tap is at full flow, then open another cold tap and do the same again with both taps running.
Come back with the findings?
make sure the incoming main and the isolation valve under the boiler are both open fully.
It sometimes takes a while to get used to a combi boiler when you have been used to great flow rates from a hot water cylinder.
Proving you have been miss sold a product is quite hard to do unless you have a written promise that it will perform a certain way and then doesn't. IMO

daveyjp

What make of boiler is it?

thedr

It's an Ideal Independent C24

My argument is that it is quite normal for seasonal fluctuations of cold water temperature. Therefore you'll have to adjust flow with the tap. And I can accept that.

However, where the situation is so chronic that an additional flow restrictor has to be fitted to the boiler, and for a manual adjustment to have to be made to this, is not normal practice. In my opinion this indicates that the kw of the boiler is inadequate.

thedr

Hi. Just in case you didn't see from the above, it's an Ideal Independent C24.

unclebulgaria wrote: »

Personally I won't fit a 24kw unit unless the customer has completely understood what it will provide.

The performance was not pointed out to me. However, I understand normal working conditions of combi boilers and that it's necessary to adjust the flow with a tap. I believe the additional flow restrictor is not a normal condition of a combi boiler, and therefore indicates that the wrong kw of a boiler has been chosen.

Find a vessel that you can measure the quantity of water in and time how long it takes to fill when the cold tap is at full flow, then open another cold tap and do the same again with both taps running.

A 2.5 litre bucket takes 8 seconds. With another tap open, it takes 13 seconds.

bod1467

That's 18.75 Ltr/min cold flow rate for one tap; 11.5 ltr/min with two taps.

However the cold flow rate only determines whether the mains pressure (flow) is too high. What matters for you is the HOT flow rate. Normal target for hot flow (e.g. kitchen hot tap fully open) is at least 11 ltr/min, and the water should be more than hand-hot at that flow.

http://www.idhee.org.uk/calculator.html ... maybe try that out and see what rating of boiler is recommended?

thedr

bod1467 wrote: »

That's 18.75 Ltr/min cold flow rate for one tap; 11.5 ltr/min with two taps.

However the cold flow rate only determines whether the mains pressure (flow) is too high. What matters for you is the HOT flow rate. Normal target for hot flow (e.g. kitchen hot tap fully open) is at least 11 ltr/min, and the water should be more than hand-hot at that flow.

Well, the hot water was taking about 3 minutes to get up to temperature before. With the restricted flow, it gets there in about 27 seconds. It takes 38 seconds to fill a 2.5 litre bucket at restricted flow.

thedr

Also, I wonder if I'd have put together a job specification prior to this, and got everyone to sign it, whether I'd be on a better footing now.