Y Plan heating and UF heating controls

[Bazza 43]

Hello Guys,

I was wondering if any of you nice chaps could lend me some advice.

So I have an open vented heating system with a 3 port valve (Y-Plan) and had a new heatmiser underfloor heating system installed with wireless thermostats. I keep having issues with the synchronous motor that operates the 3 port valve whereby i have replaced the actuator twice in 3yrs.

My plumber moved my boiler so it was beside the underfloor heating manifold with a tee piece in the pipes to serve the manifold. There is a cable run from the original wiring centre to the boiler to tell the boiler to fire up when the room stat says so.

There is another cable from a seperate supply via the underfloor heating wiring centre that tells the boiler to fire up when called on. Therefore I have essentailly 2 switchlines to the boiler. I am worried these are conflicting and possibly burning out my synchronous motor actuator.

I just spent 40mins in a queue to heatmiser and all he could suggest was both supplies should be from the same circuit and if not then a relay should be installed.

What are your thoughts?

Thanks very much

Steven

 

[davesparks]

If you have two seperate circuits feeding into the boiler then you have an incredibly dangerous situation and this should be rectified ASAP.

This will not be causing the problem with the valve motor, it is just very dangerous for ayone working on the boiler or heating system.

Has just the valve motor been replaced or the whole valve?

This could be as simple as low quality synchron motors being fitted, or being fitted to a stiff/stuck valve causing stress on the motor.

 

[Avo Mk8]

As above.
My suggestion would be to replace the whole 3-port valve assembly/ actuator with a Honeywell one (which I've done to get away from the same problem!). Unless yours is one already!

Honeywell Motorised Valve Faults - Free Heating Advice

Honeywell motorised valve faults Common Honeywell motorised valve types Honeywell make a large range of motorised valves used in domestic central heating systems. The most common by far are the 22mm 3-port, 5-wire, mid-position valve and the 22mm 2-port, 5-wire, zone valve. These 22mm valves...

freeheatingadvice.com

 

[brianmoooore]

What the plumber should have done, is to convert the existing system from Y plan to S plan. Y plan systems place stress on the valve motor, because it remains powered all the time, whether the heating system is in use or not, if the heating and water was shut down in one particular order.
Not withstanding the dangers of the system being supplied from two sources, as written about above, there is no possible wiring arrangement that could shorten the life of the valve motor.

 

[Dave OCD]

I think the OP means that the boiler switching pair comes from two sources , the stat/s for the original system and the heatmiser u/f controller, but both from the same circuit, this is perfectly ok if I'm right.......

 

[Lister1987]

You may get a better response on our sister-site plumbersforums.net

 

[brianmoooore]

You may get a better response on our sister-site plumbersforums.net

`To sort an electrical problem?!!

However the valve is switched and wherever the supplies come from, this will not affect the life of the valve motor, nor will a sticking valve, since these motors are designed to be powered when stalled.
All the supplies to any part of this system should be first of all, on the same circuit, and preferably isolated by a single switch. In the absence of the latter, labels stating that the circuit needs to be isolated at more than one point should be firmly attached at every point where the two supplies can be present.

 

[Lister1987]

`To sort an electrical problem?!!

However the valve is switched and wherever the supplies come from, this will not affect the life of the valve motor, nor will a sticking valve, since these motors are designed to be powered when stalled.
All the supplies to any part of this system should be first of all, on the same circuit, and preferably isolated by a single switch. In the absence of the latter, labels stating that the circuit needs to be isolated at more than one point should be firmly attached at every point where the two supplies can be present.

I see "boiler" and "valves" and my brain says it's a job for wetpants

 

[plugsandsparks]

It sounds like you're having issues with the synchronous motor that operates your 3-port valve in your heating system. It's possible that the two separate switchlines to the boiler are conflicting and causing problems with the motor actuator.

It is possible that having two separate switch lines to the boiler may be causing the issues with the synchronous motor actuator. As the heatmiser customer service representative suggested, it would be best to have both supplies from the same circuit.

Installing a relay could also help resolve the issue by providing a single point of control for the boiler. The relay would be connected to one of the switch lines, and the other switch line would be disconnected. The relay would then be responsible for turning the boiler on and off based on the signals from both the original wiring center and the underfloor heating wiring center. This would help ensure that the signals from both sources do not conflict, and therefore prevent damage to the synchronous motor actuator.

If you are unsure how to install a relay, it may be best to consult with a professional electrician or plumbing and heating engineer who has experience with this type of work. (courtesy ChatGPT)

 

[Zlodej]

Since ChatGPT seem to have gave the best answer so far, lets Putt all the things in one.
Most important think: Do not supply your heating from multiple supplies.
As a rule the consumption of the Valve controls is insignificant in comparison to the consumption of heating and as such does not have any need of separate supply.
SO if supply had to be upgraded, in most cases you can isolate the old one. I tend to add a fuse in between though.
If your underfloor heating is electric and if it uses major amount of power and as such requires its own supply (Only seen that once). If its gass/solar(directly heated) or heatpipe powered, then there is 99% chance creating second supply means it was wired by an incompetent person.
If you heat by electricity You should use relay and the wiring should not be done by plumber.
Its however quite common for related tradesmen (builders, plumbers) when messing into electricity to provide second supply to the system, not realizing the dangers from things like backfeeds etc...).
I have seen in fair few cases in bigger houses for this to result in 400 Volts on a mains socket system. (that would burn most valves). Realizing difference between potentials of multiple phases is well out opf scope of average plumber/builder or even of some Part P only guys.
If you have two independent supplies its well worth having a competent electrician checking they are properly isolated from each other. (In mine practice this is more often not true then true).
After that is done it is worth checking what make your valve is.
If your plumber/builder cheaped on electrician, he might have cheaped on valve as well and fitted some budget stuff like: Corgi or even worse Flomasta (even amazons choice would be better then them).
Competent person would have Limited itself to something like: Siemens, Banico (original name of one of the old Honneywell franchise manufacturers) or at least Dunfoss or as stated above Honneywell (But they have now started making a cheaper "home" version). In regards to converting Y plan to S plan, that is debatable at best. Both approaches have their advantages and disadvantages.

 

[HappyHippyDad]

The OP joined on d

 

[HappyHippyDad]

The OP joined on Dec 12 2022 and was last seen on Dec 12 2022. I don't think they are interested.
I found the thread interesting to read though.