Water gets hot when heating is turned on

[rikkys88]

Hello all, absolute beginner, just looking for some confirmation and guidance. Any is very appreciated.

I have a boiler and underfloor heating downstairs in the kitchen and a hot water cylinder upstairs.
It may be a complete coincidence, but I changed a 2 port valve actuator head for the underfloor downstairs, but recently ive noticed when I turn on the central heating system, the water also gets hot through the taps. I spoke to a plumber he said it will be the 2 port valve upstairs by the cylinder. I was worried I wired the underfloor one wrong somehow and its messing with the others upstairs.

I currently have a Sunvic SZ2301 2 port valve actuator on it by the hot water cylinder. These replacement parts are quite expensive, cheapest ive seen is £80 for the head only.

Could I replace this Sunvic SZ2301 with any motorized actuator head? It looks faily simple a straight forward plug and play with some wiring.

Thank you in advanced

 

[MeldrewsMate]

A little more detail please:

I have a boiler and underfloor heating downstairs in the kitchen and a hot water cylinder upstairs.

UFH in the kitchen only? UFH throughout downstairs?
What heating, if any, is upstairs?
Boiler in kitchen?

...I changed a 2 port valve actuator head for the underfloor downstairs, but recently ive noticed when I turn on the central heating system, the water also gets hot through the taps.

For what reason did you change the actuator?
Do you mean that the water comes through hot from the cold tap? Hot, or just warm?
Do you mean that you expect cold water from the hot tap?
Something else?

Are there two 2-port valves? One for CH and one for HW?
Are they wired from the same junction box or wiring centre?

 

[rikkys88]

Good Morning, thank you for your reply

The UFH is in the kitchen only. Boiler is in the kitchen too.
All other heating is central heating throughout the house.

I changed the actuator on the UFH as it was failing to send power back to the panel and wouldnt kick in the pump. Since changing this it all seems to be working fine apart from the issue i mentioned.

When i turn on the central heating, ive noticed that the water also heats up. It only comes out from the hot water tap and not cold.

There are 2 two port valves, one for CH and one for HW I belive. I changed one about 6 months ago, i noticed the boiler was constantly running.

They both seem to be wired from the same junction box along with the pump on the cylinder.

 

[ianmcd]

sounds like your HW zone valve is stuck open

 

[rikkys88]

Hello, I checked both the motorised valves by the HWC, I took them off and turned on the boiler and hot water separately via the Hive system, I could see both turn so the valve is not at fault. Could it be the boiler? Or an incorrectly wired UFH motorised valve in the kitchen?

 

[CBW]

I could see both turn so the valve is not at fault.

Not exactly a fault finding answer.

Try from cold and everything off, create a heating demand and feel the pipe after the hot water 2 port valve, if that starts to heat up then the valve is at fault.