Biasi 24S dhw fault

[speshfesh]

Hi all,

I guess this is a common one? Chris R and Agile were extremely helpful when I had problems like this before. That time it was to do debris in the system.

Problem: low temp dhw. Boiler fires up ok and stays on for around 30secs, off for 30secs, on for 30secs, etc, etc.
CH fine, temp for dhw showing between 50-60 degrees on guage.


I've looked at other posts on a similar subject and I have tried the following:

1. Remove secondary HE and tapped with hammer while flushing through (lots of small black debris removed and a spring!). Replaced HE.

2. Removed DV head (left side, large membrane housing) and made sure I could push spindle (this was ok and boiler fired continuously.

3. Checked flowswitch ok.

Temp leaving boiler (hand on pipe) through dhw circuit hot. Tap temp lukewarm.

New HE maybe? Going to check condition of Diaphragm tomorrow regardless.

Here's hoping Agile or Chris R see this one. Thanks to anyone else in advance for assistance.

 

[Agile]

If its hot leaving boiler and cold at tap then you have a cold water cross over, often a faulty shower or joystick tap.

Close blue valve under boiler and then NOTHING should come out of any hot tap!

Tony

 

[speshfesh]

Tony,

Thanks for the reply, I do believe I have water at the taps with blue valve in the off position.

2 mixer types- Shower and kitchen sink.

Shower cubicle dismantled at the moment so I could remove shower mixer and stop end pipes to prove the point.

Anything in particular that might make the kitchen mixer go 'faulty' (FYI small bore feeds to this)?

Appreciate any advice and your time with this.

Thanks again.

Andy.

 

[Agile]

Sometimes the seals fail in taps and showers and sometimes dirt gets on non return valve seats.

I always recommend that stand alone non return valves are fitted in the hot feeds to showers and joystick taps to avoid this problem.

Tony

 

[speshfesh]

Thanks Tony,

I'll check everything you've mentioned.

Thanks again.

We are not worthy!

 

[ChrisR]

and a spring!

That doesn't sound good! How big?

To help find which tap it is, use the fact that they'll be cooled down by the cold water going through them when it shouldn't be. So turn a hot tap on until it gets warm. Turn it off, and turn on another hot tap. Your first one should stay warm. If it cools down quickly, cold water's flowing through it. If you can feel the hot pipe, that would be quicker.
Have I made that clear ?