Luke warm water after pump/flange installed

[longdogs]

Hi

Went to look at a problem where the DHW to all taps (particularly the bath taps) was turning luke warm after a bout 4 minutes. So it starts off ok, then turns warm.

The set up is a direct cylinder with a largish header tank above and a pump which supplies all the hot and cold taps to give a better flow. There has always been a pump in place for this purpose. Water is heated by an immersion heater only.

Recently, the customer had a new pump fitted (2bar) and the fitter changed the connection from the DHW supply pipe to an essex flange.

Now, the pump works fine but the water does not remain hot. When the customer asked the fitter why there was no constant hot water, he said that the immersion heater needed replacing even though it was fine until the new pump was fitted.

After a quick look this morning it appears that the heater is heating up to
temperature. The water in the vent pipe is hot but the pipe feeding the shower & pump is not after a few minutes.

So my questions are: Could the immersion heater be only heating partiallly and could the change to an essex flange cause the problem?

I header tank does not appear to be running out of water (difficult to see).

Any other suggestions?

Many thanks

 

[dcawkwell]

Tanks is not fully hot only bit at top is hot.
Immersion isn't heating the tank up or thermostat in immersion is wrong.

 

[longdogs]

Thanks

yes, I'm thinking along same lines that heater IS probably at fault. Going to interesting though, heater is 27'' long and there is a gap under tank of about 8''

 

[longdogs]

Fitted a new immersion heater and thermostat and all worked well first of all. Then got a call to say that the water was running luke warm again despite the the fact that the immersion is getting hot. Could the fact that the pump connection was changed from the DHW supply pipe to an essex flange have an effect? Tried running the hot water without the pump on and water was still cool. I must admit that I am baffled.

 

[bolshy]

Is the pickup pipe on the essex flange upside down? How big is the cylinder?

 

[Nige F]

Hi


Recently, the customer had a new pump fitted (2bar) and the fitter changed the connection from the DHW supply pipe to an essex flange.

Why did the fitter do that ? Because he thought the pump was cavitating and that is what had caused it to fail : 45 degree hot pipe from cylinder with pump Tee underneath the slope that`ll sort it - probably the essex flange is drawing stratified water