Intermittent hot water from new boiler

[trotter]

Ideal Logic won't bring on HW if flow rate under 3 l/min your boiler may be similar.
As it uses a turbine spinning to bring it on.
Your old boiler Isar used a cold temperature thermistor that sensed the water entering the plate going cold and would come on at any flow rate.

Gotcha. Thank you.

What would you suggest I do now then?

I'm fairly confident British Gas didn't test flow rate upstairs (or down for that matter).

Would you regard just over 4l a minute through the shower, when running 'normally', as slow? What are the margins here?

My missus had a shower this morning and it ran hot then cold. It's not like hours between fluctuations. It's while you're in the bloody thing.

You shell out the money hoping for an end to the hassle, but I've been landed with more. My wife and daughters ranting and raving every morning (even more than normal!) about cold showers is more stress than having no heating!

 

[shambolic]

The shower could have even less of a flow rate on hw as higher up so the boiler is cutting off and on.
I would take it up with BG and say that it's not fit for purpose.

 

[Gasguru]

Get the water pressure/flowrate sorted. At ground level the legal minimum is around 9 litres/min at 1 bar pressure with most of the water companies.Check your stopcocks are fully open and call them up if it's still below 9 litres.

 

[Mikefromlondon]

One thing you could do to rule out mains pressure problem against flow rate problem through your shower head or pipes is to run your bath sink hot tap partially allowing say 1 to 1.5 liters per minute flow of hot water through the sink tap and the rest through fully opened shower head whilst taking a shower, does it then get cold while taking shower?

If this helps for the time being, your mrs and others won't get stressed as much until the installer sorts out the actual cause of the problem, as your old boiler worked fine, chances are the installer may not have fully opened the stop cock when he must have needed to shut the cold water supply when he swapped over the boilers.

 

[trotter]

Thanks everyone will do what you've suggested

Much obliged

 

[trotter]

One thing you could do to rule out mains pressure problem against flow rate problem through your shower head or pipes is to run your bath sink hot tap partially allowing say 1 to 1.5 liters per minute flow of hot water through the sink tap and the rest through fully opened shower head whilst taking a shower, does it then get cold while taking shower?

If this helps for the time being, your mrs and others won't get stressed as much until the installer sorts out the actual cause of the problem, as your old boiler worked fine, chances are the installer may not have fully opened the stop cock when he must have needed to shut the cold water supply when he swapped over the boilers.

Haha Mike I suggested the same thing this morning ;o)

Hopefully it works and the air can be a little less blue tomorrow morning!

 

[trotter]

Get the water pressure/flowrate sorted. At ground level the legal minimum is around 9 litres/min at 1 bar pressure with most of the water companies.Check your stopcocks are fully open and call them up if it's still below 9 litres.

Just wanted to update the thread as people had offered advice.

Got the water board out, pressure is 1.5 bar and flow rate on outside tap was 9/10 litres/min.

However what the chap did spot was that I live in a row of 3 semis and one detached, all built together in the 30s, and sharing one pipe (apols for terminology ha). Wouldn't be allowed now apparently. The houses are set about 12 feet above the street level for some reason, with a big wall holding the elevated ground up, so digging the pipe out and connecting us individually would be some job.

So, if a few of us use the water at the same the pressure to each property will fall. I suspected as much, it made no sense how the pressure would rise and fall, and chatting to my neighbour they have exactly the same problem.

So I'm kind of goosed really I think. The things you find out about your property after you buy it!

British Gas also came out, all test were fine on boiler, the lad said my shower mixer was probably a bit defective and I'd be better with a straightforward mixer than the one I have which uses wax to regulate temperature.

So, I've got the life of the boiler now with a shower that runs hot and cold! Unless a new shower mixer somehow fixes it.

The irony of all this is that I could've had the old boiler fixed for free and that always supplied hot water FFS

 

[Gas2Air]

Get the water pressure/flowrate sorted. At ground level the legal minimum is around 9 litres/min at 1 bar pressure with most of the water companies.Check your stopcocks are fully open and call them up if it's still below 9 litres.

Just wanted to update the thread as people had offered advice.

Got the water board out, pressure is 1.5 bar and flow rate on outside tap was 9/10 litres/min.

However what the chap did spot was that I live in a row of 3 semis and one detached, all built together in the 30s, and sharing one pipe (apols for terminology ha). Wouldn't be allowed now apparently. The houses are set about 12 feet above the street level for some reason, with a big wall holding the elevated ground up, so digging the pipe out and connecting us individually would be some job.

So, if a few of us use the water at the same the pressure to each property will fall. I suspected as much, it made no sense how the pressure would rise and fall, and chatting to my neighbour they have exactly the same problem.

So I'm kind of goosed really I think. The things you find out about your property after you buy it!

British Gas also came out, all test were fine on boiler, the lad said my shower mixer was probably a bit defective and I'd be better with a straightforward mixer than the one I have which uses wax to regulate temperature.

So, I've got the life of the boiler now with a shower that runs hot and cold! Unless a new shower mixer somehow fixes it.

The irony of all this is that I could've had the old boiler fixed for free and that always supplied hot water FFS

Bit like buying a car and not knowing doing any research and just lumping in to what sounds good on paper.

 

[Mikefromlondon]

Without me reading all the posts & replies again here, do you think a pump has been suggested at the incoming mains?

alternative you need a boiler that trips in at low flow rate would be the one to go for. what was your old boiler called ?

and you need a combi boiler that can fire up from flow rate as low as 1 l/m or even lower but not whilst you may have a dripping taps. I think many people know which one I am referring to. (Ideal Issar HE30)

 

[Dan Robinson]

as low as 1 l/m or even lower but not whilst you may have a dripping taps. I think many people know which one I am referring to. (Ideal Issar HE30

Are you suggesting people by an Isar?

 

[trotter]

Old boiler was an ideal which I was told was a hunk of junk ha

But yes it kicked in at low flow rates

 

[shambolic]

as low as 1 l/m or even lower but not whilst you may have a dripping taps. I think many people know which one I am referring to. (Ideal Issar HE30

Are you suggesting people by an Isar?

Yaaaaaaaaasssssss

 

[Agile]

Using a pump to suck water out of the main will be very antisocial to your neighbours.

There must be hundreds of people like this in your situation.

If all houses take 9 li/min from an open tap individually and then together, I wonder what individual flow rates they will get.

In that case I would say that the Water Company is not living up to their minimum standards.

Getting them to do anything about it is another matter though.

Tony

 

[Agile]

To clarify, the minimum is not 9 li/min and 1.0 bar at the same time ( ie dynamic flow rate ) These minimum standards do seem to vary a little according to who you ask.

Its a static pressure of 1.0 bar and an open pipe flow rate of 9 li/min.

Through a combi boiler the flow resistance will seriously reduce the flow rate to perhaps half of the open pipe. Even less through a shower.

Tony

 

[Mikefromlondon]

Well if he installs a pump, and his neighbours suffer more shortage of water or pressure, they will make fuss about it with their water company to rethink about the size of the supply pipes.

So the alternative would be to store cold & hot water in loft tanks and then if necessary use pump for the shower, which is a bad idea as most people are now ripping out extra expense and tedious arrangements of having to store gallons upon gallons of hot and cold water stored in loft or other places, breeds bacteria and attracts mould growth, with other debris falling in if not covered properly, occupants suffer from frequent health problems such as throat irritation. Some people would say what do I know? I will ask what do they know that I don't know? All I know is that a few people have been hospitalised through serious bacterial infections when mice have been found dead inside a storage tank that was left open by some plumber.