Hot water issue

[Ches smith]

Hello all,

I’ve had this problem for a long time and I’ve had enough so trying to fix it.

hot water in the kitchen will only work if I turn on a hot tap in the bathroom above. I’ve checked the pipes. And when my parents had the bathroom and kitchen fitted years ago (cowboys would be a complement) they did an awful job of the pipe work.

current set up is this.

15mm cold water supply to the boiler. Boiler is a main multipoint ff fan assisted water heater (no central heating in the house). 15mm hot supply comes from the boiler for about a meter then changed to 22mm and heads in to the bathroom. 15mm tee to the basin and then 22mm continues to the bath (not sure if or when it changed to 15mm to the bath tap). 15mm then heads down stairs to the kitchen hot.

if you turn the hot tap on in the kitchen you get a trickle of cold water but I fear it’s not enough pressure to activate the boiler.

can anyone help or advise how to fix this? Thanks.

 

[CBW]

Yep, could be not enough pressure/flow to activate flowswitch inside heater. Could also be crossed pipes.

 

[Ches smith]

Yep, could be not enough pressure/flow to activate flowswitch inside heater. Could also be crossed pipes.

thanks Chris. How would I increase pressure? Continue the 22mm to the kitchen?

what do you mean by crossed pipes?

 

[CBW]

Only way you could increase pressure is check your mains supply is adequate, eg doesn’t need an upgrade, if that’s fine, you may only be able to get a home boost pump.

Crossed pipes are where the hot and cold are inadvertently crossed over. For example the hot and cold upstairs are ok, but to the kitchen may not be. Eg the hot is piped to the cold and vice versa.

 

[Ches smith]

Only way you could increase pressure is check your mains supply is adequate, eg doesn’t need an upgrade, if that’s fine, you may only be able to get a home boost pump.

Crossed pipes are where the hot and cold are inadvertently crossed over. For example the hot and cold upstairs are ok, but to the kitchen may not be. Eg the hot is piped to the cold and vice versa.

ah right. I don’t think the pipes are crossed as we do get hot water as long as the hot tap in the bathroom is open.

the hot water pressure is brilliant in the bathroom just not in the kitchen. Would extending the 22mm pipe from the bathroom to the kitchen make any difference?

 

[terryplumb]

ah right. I don’t think the pipes are crossed as we do get hot water as long as the hot tap in the bathroom is open.

the hot water pressure is brilliant in the bathroom just not in the kitchen. Would extending the 22mm pipe from the bathroom to the kitchen make any difference?

No it won't make any difference, the hot output from multipoint is 15 mm.
If bathroom taps flow triggers the multipoint and kitchen tap doesn't ,then your problem is the plumbing to the kitchen tap. What flow rates do you get from hot and cold kitchen taps ? Any restrictive Flexi hoses ,isolation valves ,non return valves or filters upstream of the kitchen taps ?

 

[Ches smith]

9ltrs per minute cold water. About 2ltrs a minute hot. But it comes out cold until the tap upstairs is opened.

short flexi from copper to tap but I’ve taken that off and get the same 2ltrs a min coming out of the end of the copper pipe

 

[terryplumb]

2 lt/ min isn't enough to trigger the multipoint.
There is restriction on the hot pipework to kitchen tap.

 

[Ches smith]

2 lt/ min isn't enough to trigger the multipoint.
There is restriction on the hot pipework to kitchen tap.

Replace the existing 15mm pipe with new 15mm pipe and that should fix it?

 

[CBW]

Might be an isolation valve then not fully open, or even appears fully open but isn’t.

 

[terryplumb]

Before going to that extreme ,first rule out any isolation valves , particularly round red handled ones ( gate valves), flexible hoses that are twisted or bent at sharp angles , filters ,and the tap itself

 

[Ches smith]

As far as I can tell the only isolation valve is the one I fitted to connect copper to flexi at the tap. However, this problem was present before the new taps I put in last week. I thought the problem may have been the taps, alas it was not.

 

[terryplumb]

How much of the Pipework is visible ,from where it Tee's into bathroom Pipework down to kitchen ? Blockages on 15mm copper ,domestic hot water pipes are fairly rare. Blocked filters ,isolation valves ,and crushed pipes are common.

 

[Ches smith]

About a meter visible but it goes into a boxed in section that I can just about see through the cobwebs. I’ll vacuum the boxes in section tomorrow and try to find a valve

 

[terryplumb]

Show us a pic of the TEE that branches off to kitchen from bathroom