motorised actuator valve - fault ?

enmac

Thers are three sunvic motorised actuator valves fitted near the cylinder in my house.
I have recently noticed that the valve casings are quite hot to the touch - this happened accidently when my hand brushed off one.
Since this happened I have checked them a few times when the cetral heating has been turned off and all connecting pipes cold and they are still hot - is this a botched install ? - It seems the motors are drawing power when the valves are fully open/ closed thus causing the excessive heat ?

Avns1s

Sounds like they're activated even though the heating is off.

Correct way of wiring would be to either

1. wire from the Heating controller to the motorised valve and then from the relay contained in the motorised valve to your boiler bring on your boiler as it activates. If this is done for each valve on an individual basis it means that you can activate the valve for any zone and the boiler will come on and feed that zone.

2. feed the motorised valves in parallel with your boiler, i.e. that as you send power to your boiler from your controller, you are also sending power to one or more of the valves.

Either way, they should only be activated when the boiler is on.

Best to get an electrician to have a look.

dingding

Alternately,

You could bring on your boiler with the switch in the valve. i.e. if the valve is energised then the boiler will come on.

The valves have a tendency to stick in one position or another. But this is hardly causing the current problem.

I would have an electrician revisit the wiring as it does not seem right that the valves would be energised when the boiler is not running. (as suggested by a previous poster).

It is unlikely to be dangerous (unless there are other problems) but you are using more electricity than required to run the system.

If you gave a bit more detail about how your heating system is controlled we might be able to advise further.

watty

I've seen a lot of these fail, usually shut. Most have a manual lever, if it has leaked and corroded it may not work (WD40?). Usually Manual Operation was OK till I replaced it.

I've seen some fitted the wrong way round and even on the wrong place, or wired wrong. You need someone that can design/repair boiler systems, not just a basic plumber. If memory serves me there are about 5 wires and the electric feed should be off if the main time switch is off. A themostat or control switch powered by the main timer/on off should power them.

The auxilary pair of wires should be in parallel across all valves and then in series with pump so that if ALL valves are electrically off the pump is turned off.

dingding

Another option is that the systems is working normally and comming into the summer you just turned of the boiler with the switch on the front.

Depending on how your system was wired, your control system is probably still calling in the boiler, pump and valves, but nothing is happening on the heating side because the boiler is off.

The valves and other components are warm becuse they are energised trying to raise the temperature without the assistance of your boiler.

enmac

Thanks for the replies.
I've had a bit of a poke around and seem to have found out whats going on.
The baxi gas boiler is incorporates the pump and timer - power to the actuators is fed from a point after the main on/off switch but before the timer.
Two of the actuators are in series with their respective room stats and the third is in series with the cylinder stat.
The actuator valves are motorised open spring shut and therfore will always 'power on' when the stat is set above the existing temperature.

Really they should be powered from a point after the timer.

I really agree with the point about plumbers designing the central heating systems - some are very competent and can do it but not in my case - builders should be getting engineers to verify designs.

The existing system is a real pain too as it will not allow you to heat the water without the rads getting hot ( unless you set rooms stats to min)

This is a new housing estate (5 yrs) with over 100 houses - all plumbed like mine - so much for building regs !!

dingding

A solution might be to hard wire the timer and replace the thermostats with a thermostat that has a timing function, i.e. you can set it for differrnt temperatures at different times. I have a couple of thermostats with timers that I use, one for upstairs, and one for downstairs. It has the added advantage that the temperature and time, together with boost, is controlled from the location that is been heated, i.e. you don't have to go downstairs at night to control the heating.

The wiring for the stat in the hot water tank could probably be changed to accomodate this system. Might be better to get a competent electrician to look at it rather than a plumber.

Best of luck with it

Steve

This is an upgrade I have on my project list - can anyone point me to a good source for these valves?
I already have a timer / controller waiting in a box & want to automate the rad shutoff valve.

enmac

try heatmerchants - they usually carry a comprehensive range - make sure to get momo type - motorised on motorised off.

dingding

The momo valves need a feed to power on and power off, while you can also get a power on with a spring return, depends on the cabeling in the house. Heatmerchants have these but most good plumming suppliers shouls have a motorised valve.

Steve

Sorry to hijack this thread but I was told there's a retro-fit one that fits onto an existing 1/4 turn ball valve - (the guy said he saw one but couldn't remember where).
Any ideas?

Dingding, The wiring won't be a problem as there's none yet. I'm looking at a lonely roll of 4x0.75 sitting unused in work - I reckon I could give some of it a good home....:D