Low flow rate

[ketansoni]

I have a Potterton Puma 80 combi boiler and am finding the flow rate for the hot water is considerably reduced when any other tap (hot or cold) is opened. I have checked the flow rate from the cold mains and it seems good enough. Can anyone suggest why this may be happening. I checked the isolating valve into the boiler any it is fully open.

In addition I have also found that the hot water temperature is constantly high and there is little effect when adjusting the temperature control on the front panel. Any suggestions?

Many thanks

K

 

[vijay]

this may be a quirk of all or most combi's. I could name you at least 10 housholds where if one hot tap is on then all other drop to delivering very little if not at all flow.

 

[Ant]

Are you sure the dial you are turning is for hot water - on my combi only the central heating temp can be adjusted. The temp at the tap changes according to flow rate - ie slower flow = hotter water - open the tap a bit more and the temp is slightly lower.
As mentioned the problem with some combis can be the reduced flow when other taps are open. Some newer boilers appear to have a much greater flow than some older models.

 

[ketansoni]

I can understansd you would expect reduced flow if 2 hot water taps were opened but I wouldn't expect the same if the cold water tap was opened. I was adjusting the hot water temp as opposed to the ch temp control.

As a separate question, can someone explain to me what a lockout is, how it happens and what needs to be done to rectify the problem.

Many thanks

K

 

[breezer]

'fraid its true, if you turn on another tap even if it is the cold one, you are depleating your combi of water, so the flow rate will go down. (its like the old trick of flush the toilet when the mrs is in the shower)

If i turn on our outside tap we actually get NO water out of the hot water tap in the bathroom, this could be overcome by supplying the boiler with a 22mm water feed, but as im a not a plumber, we just dont turn on the outside tap when the shower is on.

With regard to lockout, i asked the b.gas man why it does that, he said its caused by a number of things, and is hard to determine which one caused it. (unless it is blatantly obvious)