Ariston combi - little H/W upstairs

[dal5band]

We have an Ariston micro genus 23 which delivers H/W to the kitchen without problem - good flow and hot.
Upstairs the flow is OK but the H/W runs almost cold, both bath & wash basin. The effct is the same with the bath or basin on its own or together. Even if you turn the kitchen tap on first, turning on the bath tap makes H/W go cold.

Seems some sort of pressure senser is cutting off the heat if an upstairs tap is turned on. The boiler is downsatirs, 5m from kitchen, bathroom above kitchen.
Would appreciate any suggestions as to cause and further tests we can do.

 

[Paul Barker]

Is there a mixer tap on the bath without built in check valves? to test, Shut off cold supply to boiler opn hot tap in kitchen no water should flow. Now open both hot and cold bath tap, does water now come out of kitchen tap? Fit two check valves one on hot one on cold to bath mixer tap.

Secondly ensure that flow at boiler is restricted to 10 litres a minute when bath tap is turned on full.Now how is performance?

 

[dal5band]

Yes there is a mixer tap on the bath !
- will do tests and let you know what happens.

 

[dal5band]

After a bit more exploring we have discovered that the H/W to the kitchen is a direct new run and works fine.
The H/W to the bath goes from boiler, accross the house on the ground floor, up to 1st floor , up to loft, back accross the loft down into the bathroom. So this is a long run - probably using old pipes along the way. This may be causing the boiler sensor switch and/or diverter valve to drop in and out.

 

[Agile]

The boiler does not know where its water is going!

But the hot will take ages to get to the tap and will get nicely cooled on the way!

Tony

 

[Blasphemous]

The boiler does not know where its water is going!

But the hot will take ages to get to the tap and will get nicely cooled on the way!

Tony

I'm with Tony on this. That pipe run needs renewing. I think you have solved the problem yourself. The Kitchen has good flow and heat due to the short direct run from the boiler. Re-route the bathroom hot and I would wager the problem will be sorted.

But has this problem just started?

 

[Agile]

Is there a mixer tap on the bath without built in check valves? to test, Shut off cold supply to boiler opn hot tap in kitchen no water should flow. Now open both hot and cold bath tap, does water now come out of kitchen tap? Fit two check valves one on hot one on cold to bath mixer tap.