Boiler change question 2

[Bob Minchin]

Following on from my pump location Question,

I'll also be installing zone valves for the first time. Simple on off ones in a variant of S plan. I read here from time to time about problems with failure of valve mainly seem to be motor units.

Is there a more reliable brand that sticks out above the others or are they all more or less the same? reliability is more of an issue than price. I'm looking for overall value.

Are there types that are not spring return but driven in each direction

- would those be more reliable?

I will be tinkering with my own control system and can envisage that some valves could stay in one state for long periods (weeks) so does the team think that it is worth exercising the valves once a day as a matter of routine or is wear more of a problem than sticking?

TIA

Bob

[Onetap]

Honeywell. Try BES.ltd.uk

Should be, but aren't. Only Sunvic make domestic ones, SFAIK.

I wouldn't bother. If they're to be left open for weeks, you could disconnect the power and open them manually with the lever on the side. When powered up again, they go back to auto mode, power open spring return shut.

[John Rumm]

Honeywell seem to be pretty good. Having said that, there are some very similar clones around now.

So called MoMo valves:

Lots of modern control systems do exercise the valves from time to time, so yes its probably worth doing.

Note also that while most valves are "normally closed" and open when energised, you can get some that run the other way.

[SteveW]

We have 9 Honeywells (8 have been in for just over 10 years) and we have had only two failures in that time. The replacement motors cost just over a tenner each and took less than 10 minutes to install.

There's probably more to go wrong with the non-spring return ones as they are slightly more complex.

I keep intending to get around to a more sophisticated system and that is an option that I intend to design in - probably because I come from an industrial control background and have specced many valves that do require exercising on a regular basis. However, we have timer/stats for each room and a hard-wired system, so currently most of the valves remain closed for many months at a time and it hasn't been a problem.

SteveW

[Roger Mills]

the power and open them manually with the lever on the side. When powered up again, they go back to auto mode, power open spring return shut.

Be careful if you do that. If it's a standard S-Plan system, you'll be relying on the auxiliary switch - which makes when the valve is open - to turn on the boiler and pump. Not all valves open sufficiently in the 'manual' position for the switch to make. [The manual lever is only really intended to open the valve for filling and draining purposes, not for actually running the system (but can be useful for that if the motor fails, as long as you've got an alternative means of switching the boiler and pump)]

[geoff]

No there is only the reverse run clutch

[Man at B&Q]

"Only"? I would say that is quite poor.

MBQ

[Bob Minchin]

Reverse run clutch? I was looking at some sunvic diagrams and from an electrical point of view, I did not see then ability to reverse the motor (only two wires) and so I presumed that the motor turned valve in the same direction and simply stopped when the next position was detected by microswitches/cams.

.... further thought..... Maybe you mean the device that makes the synchronous motor start in the right direction when it does not have a start winding.

[geoff]

Err yes - my choice of words when pissed is my own

the spring which jump starts it back in the right direction

must be 10 years since I saw one

[SteveW]

Both times it has been the synchronous motors and they're standard items that'll be much the same for every manufacturer. Two 10 minute changes at around a tenner a piece is fine for me over 10 years!

SteveW