DWH calls when open cold tap

[leakeee]

Hi all!

Fitted a ideal logic combi, iv noticed when i open the cold kitchen sink tap the boiler calls for hot water, the burner doesnt

come on but the fan runs and continues to run for about a minute after.

The boiler is fitted with the cold coming up from the bottom into the boiler then continues up to the bathroom above.

the hot also goes up and down from the boiler.

The hots and colds are capped upstairs so was thinking cause of the dead leg.

Any thoughts?

cheers

 

[Kyle87]

Water hammer

 

[plumber0808]

Fitting a check valve and mini expansion vessel on the cold will sort that out.

Dead legs do them no good though as air becomes trapped in the section,cut them out or right back if you can.

 

[lame plumber]

prv is a;so a requirement fm some manufacturers, intergas suffer same issue

 

[leakeee]

the pipes run from the boiler under the units then up into the the sink unit. so it would be that section?

 

[Billy Bob Bob]

you have what is known as a dead leg,a run of hot water pipework not doing anything and full of air this is you issue find it cut it out job done

 

[dancinplumba]

prv is a;so a requirement fm some manufacturers, intergas suffer same issue

Intergas suffers nothing, bad install without

 

[lame plumber]

only found the issue with first install, then read the early manual properly and popped in a prv manuals are better written now of course, got a proper hurdy gurdy translator in