Noisy pump on 'water only' setting

[Last Triumph]

Having now identified the source of my hot water issues, I have opened this thread as the title for this thread is more appropriate.

I have a fully pumped, vented CH system in a two story house built in 1990.

Whenerver I run the system as 'water only' the pump goes very noisy and sounds like it is really straining.

A soon as the rads are switched on (no TRV's by the way) via the controller, all goes quiet again.

If I open the bypass gate valve fully it goes quiet but the water in the cylinder doesn't get hot.

If I open the bypass just a little, the pump stays noisy.

The background to all this is that I need to run the hot water for longer than the CH to ensure a constant and ready supply of hot water for my new mixer shower.

As previously suggested in the other thread - it sounds like there is a severe flow restriction within the cyl coil or a faulty honywell 3 way valve that isn't opening fully?

Does this sound likely given the symptoms?

 

[dal5band]

Just check there isn't a valve in the return from the HW heat exchanger coil. Sometimes a valve is put in to help balance the system and it may have been turned down too much. Also are you running the pump too fast - try it on 1 and see if it's enough to run the heating.

 

[Last Triumph]

There is a valve and I've checked it's open fully.

The pump is on number 2 setting. The only difference changing the speed of the pump makes is the pitch of the noise.

It only goes away when the bypass is fully open which gives me no hot water.

 

[dal5band]

I just read your other post about the HW not being hot enough or too slow to heat after the kids bath.
Seems to me the two problems are related - there's probably some sort of blockage in the HW coil circuit. Try running the pump on max just through the HW circuit to see if it clears otherwise it's a drain down and have a look - not a job for winter, though.

 

[chrishutt]

Last Triumph, starting multiple threads on your problem isn't going to change what the problem is. You've been told it's a blockage but you want someone to tell you something different, so you start a second thread so people won't see that you've already been told what the problem is. That is an abuse of the forum.

 

[twgas]

try using the immersion,then you wont need your pump for the hot water,- no more noise!!!!!!!!!!!