Tap or combi boiler problem??

[tukky142]

Hi,

I have a Potterton performa 28i combi boiler installed in the loft.

I have two problems -

1. The boiler has a long delay between the stored hot water coming out of the tap (which is almost instantaneous) and the newly warmed water. There is a long delay of at least 30 seconds and this is the closet tap to the boiler in the bathroom. The tap also has to be turned to a fast rate to get the boiler to kick in. Is this a problem with the boiler or do they all have along delay?

2. In the kitchen I have a price pfister faucet model 533-50WW (mixer tap) with spray nozzle. The tap is connected from 15mm supply pipe into a 3/8" tap tail connection and then tail goes down to an even smaller diameter pipe (US standard pipes sizes I suppose). The problem is that when you turn the tap on to hot water it will not fire the boiler up. The water runs and you get the initial shot of stored hot water and then it goes cold. I have disconnected the tap and put a pipe into a bucket from the supply line and turned on the lock valve the water does run hot and then the boiler kicks in and stays hot?! The thing is the tap always used to deliver hot water - so what has gone wrong? I have cleaned out the tap and check for blockages. I have tried to get hold of a replacement vacuum cartridge but this top has been a task! The price pfister website does not deliver parts to the UK!! So I sent an email to customer services in the USA only to be told to contact Canada. When I phoned canada to order the part I was told that they don't ship to the UK and contact USA??

Basically I am on the verge of buying a new tap with 15mm supply lines to see if that will kick the boiler in. I just wanted to check that it wasn't the boiler that was causing the flow problem.

Thanks

 

[ordo]

Problem 1.
With all combi boilers there is a delay with the hot water and this depends on the flow rate of your boiler say for example @35 degrees temp you will get 8 litres a min. So this you must take into factor. But it sounds allright with the timescale you have.
Problem 2.
You must not be getting a suffeciant flow through the hot water tap. Combis work off a diaphram which activates when you turn the water on. If the flow is not great the diaphram will not open. Try upping pipe size.
Cheers. Ordo

 

[tukky142]

Thanks

The thing that is puzzling is that it used to work? What we have to do is turn on the tap in the downstairs toilet and then this is enough for the boiler to kick in and we get hot water in the kitchen.

I think the best thing is for me to replace the tap with a new one that has 15mm supply lines right upto the tap.

 

[ordo]

Tukky,
Try checking the diaphram in the boiler for the hot water to see that its opening ok. Try checking the hot water thermistor also. This can be done with a multimeter and read it in ohms across the connections.
Could be that maybe..

 

[kevplumb]

might be worth checking the filter on the cold inlet

 

[tukky142]

How do you chekc the diaphram?

Do you mean the cold supply to the tap?

 

[kevplumb]

1 see if the switch makes on h/w demand

2 the cold into the boiler has a filter

mans instructions here

 

[chrishutt]

I don't know the Performa, but in general the diaphragm is housed in the diverter valve (the large disc shaped part, held together with lots of screws). chances are the diaphragm is developing a leak, so that it fails to respond to slower flow rates. Certainly worth checking it visually (i.e. opening up diverter valve), but probably best to get spare first so that you can change it at same time.

 

[tukky142]

I have checked the manual and it is part of the Diverter valve assy.
If you think this may be causing the problem I will fit a new diaphram.

Thanks