Low hot water pressure / flow

[nickkell]

Hello,

I have a Baxi Combi Instant 80HE boiler, which is causing me no end of bother. Earlier today I had the h.w. diaphragm replaced by a professional, as the hot water was not working when the taps were turned on. This problem has now been fixed and the hot water is again flowing.

However, the flow is now so low that our "power shower" is now little more than a dribble and this was never the case beforehand. I didn't realise this when the engineer was in the house and only realised when my partner went for a shower. Additionally, I have now noticed that all of the hot water taps are flowing much less powerfully.

The general water pressure appears to be fine, as the cold taps are still working at full pace.

What could have caused the drop in hot water tap pressure? And how can I fix it? Is it something really simple that I am unaware of or something more sinister? The pressure reading on the boiler itself is fine but I don't know to what extent this is connected to the 'power' of the hot water coming out of the taps.

Any help would be much appreciated!

 

[kevplumb]

check the cold water isolation valve on the boiler is fully open first

 

[gigz]

Not really familiar with this boiler but have you checked (if there is one) the valve on the cold flow just as it enters the boiler ? Not the filling loop by the way, if the professional has closed this he may not have opened back up all the way. You could phone him and ask his thoughts.

 

[nickkell]

Thanks very much to both kevplumb and gigz!

It seems that the solution is sometimes simple.

I would admit to feeling like an idiot but I am quite happy to admit that I am wholly ignorant when it comes to boliers and the like!

I am assuming that you both suggested the same solution? Is the "cold water isolation valve" the same as the "valve on the cold flow"? I took it to mean that in any event.

I don't know if the engineer didn't wholly open the valve again or if I knocked it myself but it was only half open.

I am taking it as given that the hot water flow will never be quite as strong as the cold water flow? Am I wrong to think this? The hot water flow, with the valve open, is much improved but still not powering out like the cold water. Definitely liveable however.