New Gas Combi Boiler Bad Hot Water Pressure - Need Help

[GatesheadHeating]

You need to get a bucket or saucepan of known volume ( can check by filling using a measuring jug. ).

Then time how many seconds it takes to fill this container. Measure at kitchen cold tap and then at bath cold tap and then at bath hot tap.

Thanks for that Tony - have done so & here's the results:

1ltr jug
Cold Kitchen Tap: 6.5s
Hot Kitchen Tap: 9.5s
Cold Bath Tap: 5.5s
Hot Bath Tap: 9.5s
(also did cold & hot bathroom sink taps which were exactly the same as the bath)

We have concluded that our hot water pressure in the kitchen only appears so vastly improved cos it literally used to trickle taking an eternity to fill the sink for washing up!

Anyway, these figures work out that we're getting approx. 9ltrs/min of cold water from the mains & 6ltrs/min of hot water from the boiler - nowhere near the 9ltrs specified by another member on this thread.

Am I right in deducing that its more than likely the pipe coming off the mains, up our drive & into the property? Or is there a setting on the boiler to increase the hot water pressure?

I'd like to add that its been in the 20's heat wise for a couple of weeks now so surely there's no reason why the boiler should've "slowed down" to that?

There are no settings on the Junior, as it is Worcesters' entry level boiler, however, being a combi, running on mains pressure, the flow rates of hot and water should be pretty much the same. The boilers' resistance to the hot water flow should be minute and it should give 11.5 liter per minute on 30 cell degrees rise.

I would check that the cold water inlet gate valve to the boiler and / or any other valve on the hot water side (if you have one) are fully open.

If non of this work call an engineer to clean the filter, Flow Restrictor housing, or replace the Flow Restrictor.

good luck.

Rami

 

[FrankyTheFrog]

There are no settings on the Junior, as it is Worcesters' entry level boiler, however, being a combi, running on mains pressure, the flow rates of hot and water should be pretty much the same. The boilers' resistance to the hot water flow should be minute and it should give 11.5 liter per minute on 30 cell degrees rise.

I would check that the cold water inlet gate valve to the boiler and / or any other valve on the hot water side (if you have one) are fully open.

If non of this work call an engineer to clean the filter, Flow Restrictor housing, or replace the Flow Restrictor.

good luck.

Rami

Thanks Rami - I'll look into the Flow Restrictor!

The boiler was only fitted February of this year tho so should there really be any cleaning necessary?

 

[Agile]

I have to disagree!

Those flow rates are just what I would expect to find and the reduced flow rate on the HW is caused by the flow resistance through the boiler.

I cannot understand how we hear of so many installers who dont understand pressure and flow and properly check and assess them before fitting a combi.

Many are probably just short of work and fit the combi knowing it will not perform well but at least they get the work. If it will not work then I dont fit it or I suggest supply pipe improvements.

The boiler's rated output of 9 litres assumes an adequate dynamic flow rate being available from the mains. Most installers dont understand how to measure that.

Your only solution is to have the mains supply checked and upgraded. Very rarely its just a stuck stopcock but in most cases a new plastic supply pipe needed between the street and the house. Usually £600-£1200 !

Nobody seems to do it but I view your installer as being to blame for the poor performance by not checking/understanding the supply requirements and should contribute to the costs of the necessary improvement.

Whilst I always point out any problems when quoting, most owners choose the cheap option from other installers who say it will be fine. That gets them the work and they seem very thick skinned when it does not work well.

Tony Glazier

 

[FrankyTheFrog]

There's no comeback on the installers Tony as it was through the WarmFront government grant - we happened to be eligible at the time & thought we should take it up but now wish we flippin' hadn't cos are having to pay out loads to rectify botched jobs both on the heating side & water plumbing side!!

We tried to look on it positively thinking we had at least got a new boiler & radiators but if the boiler is to blame cos our pressure coming from the mains is too poor to have it then it was a waste of time & upheaval plus money shelled out recently

 

[Agile]

We hear of many people on here who have had bad experiences with warmfront.

Of course it is working but its just that the water flow rate is only 66% of what it could be.

So from a practical point of view its doing the job. Just not as well as it could do within its capabilities.

You now need to see if the stopcock is restricting the flow much. Sometimes replacing with a full flow lever valve will improve it by 10-20%.

Otherwise its a matter of considering how the mains can be upgraded.

If its an old lead pipe then its cheap to replace if you can do the digging just up to the edge of garden stopcock ( if any ) as the materials are usually less than £100.

The expensive part is the water Supplier new connection to the street as they mostly start that at about £500 !

I know someone very well who dug down inside his garden and burrowed under the edge of the pavement for about 300mm and made the connection to the short plastic tail they had used when fitting the meter to the old lead pipe !!!

Tony

 

[FrankyTheFrog]

You now need to see if the stopcock is restricting the flow much. Sometimes replacing with a full flow lever valve will improve it by 10-20%.

Otherwise its a matter of considering how the mains can be upgraded.
Tony

Thanks for the advice Tony

We have had the stopcock inside the property replaced to no avail. The external stopcock is quite far underground - the plumber needed a long pole thing to turn it off/on when doing the heating & bathroom upgrades.

Our drive is shared, steep & at least 7 metres from the public footpath to the front of our property. Any advice there?

 

[Agile]

Forget the drive.

What about the garden?

Water mains need to be burried a min of 750 mm down! It does need some digging.

Is it currently lead?

Sometimes, but rarely, the stop valve just inside the property is not opening fully. Excavating that would enable the flow into it to be measured. That will demonstrate just what improvement could be obtained with a new supply pipe.

Tony

 

[FrankyTheFrog]

Forget the drive.

What about the garden?

Water mains need to be burried a min of 750 mm down! It does need some digging.

Is it currently lead?

Sometimes, but rarely, the stop valve just inside the property is not opening fully. Excavating that would enable the flow into it to be measured. That will demonstrate just what improvement could be obtained with a new supply pipe.

Tony

Garden is an utter nightmare - on various levels!

No idea if the current pipe is lead but would assume so - the property was built in the 1950's & as far as we know from old neighbours no pipe work has been done.

How would we go about locating the stop valve inside?