"Ticking" noise from mid position / 3 port valve (

[jonnyd963]

Hi there - new to the forum, but I hope there is someone out there who can help me with this!

I've always had a problem with a "ticking" / "tapping" noise (not an air-hammering / water-hammering type noise, more tinny & metallic) coming from a Tower 3 port / mid position valve. This is annoying, but given the difficulty in accessing the valve body, I just ignored it. Valve recently failed, so I thought I'd swap it out with a Honeywell V4073.

The new unit is making an identical noise, but with an unfortunate increase in volume(!); which is now loud enough to wake people in the house (noise is transmitted efficiently through the pipework, so affects every room). The valve is allegedly good quality, and brand new.

I have tried everything (I can think of):

1) flushed all the air out of the system under 'closed' conditions (i.e. mains fill on closed system (open), all radiators bled & sealed (valves left open); only opening is drain down on lowest point - flushed at mains pressure until clear of bubbles for 2-3 gallons),
2) checked for transmission of boiler noise (no noise from ravenheat system boiler),
3) reduced pump flow rate (no change to noise generation)
4) Flushed system at full 22mm pipe bore (not via drain valve) to remove any grit / debris / sludge
5) Checked all wiring & functions, all working as they should with correct voltages & valve movements when triggered by cylinder / room stats & boiler call (control unit settings)
6) 15mm bypass has been fully opened up to ensure adequate flow through the heat-exchanger (avoiding kettling)
7) verified AB port is connected to boiler output, not return
8) verified correct setting of air release valve on top of the boiler, and at the expansion vessel (integral to the system boiler)
9) bled the standpipe in the loft
10) run the system on minimum & upper limit of operating pressures (no change in noise generation)

When valve is in either A, or B position (i.e. ball seal wedged against pipe opening), no noise.

When in mid position (between common AB, A & B ports - for CH & HW), I get the ticking. I upgraded the brand to avoid this problem, but as far as I can tell the two units (the tower, which I replaced, and the honeywell replacement) are identical - despite the honeywell costing a good £30 more.

It seems I've more or less ruled out electrical problems, and air in the system; as well as water pressure / flow; so I'm thinking that it has to be the valve(?)

- is this a common problem (i.e. 'just the way it is')? Or is this a faulty valve that needs to be replaced (again)? Could it be valve orientation (currently mounted vertically, with AB right, B top & A bottom)?

I'm now pretty much out of ideas, so any help with a cure would be much appreciated!

 

[OilLecky]

See the similar postings John. The bad news is that it is usually a micro switches in the electrical head. One is supposed to cut the voltage down to about 90 volts to hold the valve in the mid position. If it is switching the power off instead (open circuit diode) the valve returns under spring pressure and the motor winds up again etc. etc. etc.

 

[jonnyd963]

Thanks OilLecky - I've read up on a few of the forum threads, and the ticking noise (in most of the posts) is almost always accompanied by a fault in valve function (as you say, often the micro-switches) - not so with mine.

I suspected that it might be a dodgy valve - but thought Honeywell would be reliable straight out of the box (and my plumbing seemed like the more likely culprit!). Will swap it out for a new Danfoss (shoe-type this time) and see if that one runs quiet - the honeywell will be winging it's way back to screwfix for a refund shortly!

Will let you know how I get on...

 

[OilLecky]

John,

Its a pain if you've bought a duff valve. Try taking the cover off of the head and watching to see if the motor is oscillating about the mid position. If it is, then it is one of the micro-switches or the associated resistor / diode network that's faulty. If so, try to swop out the electrical head only with your dealer as it's a lot easier than changing the (wet) valve!!

 

[jonnyd963]

Thanks for the advice - I have checked the motor prior to draining down, and there did not appear to be a problem. As it turns out, it was worth looking, as it has saved me some work (and some expense) replacing a valve that seems to be operating as it should.

So, I've done some more head-stratching - and fiddled with the system a bit to try to narrow it down (on the basis that the valve motor / electrics are working correctly).

It seems that the noise stops when the upstaris radiators are turned off, and flow is restricted to the downstairs circuit. I feel at this point that my slur on the good name of honeywell may deserve an apologetic retraction - seems like the valve is functioning correctly, and without noise. This rules out any loose parts on the 'innards' of the valve occilating in the flow.

Trouble is, as soon as I introduce a flow on the upstairs circuit (open rad valves, on ANY upstairs radiator), I get the ticking again. This seems to indicate that the problem may be unrelated to any valves / pumps on the system (no Thermostatic valves fitted on rads). I can only conclude that there must be some debris in the system that has been there since the installation, trapped in the feed from the boiler, in an elbow feeding the upstairs circuit (i.e., there is insufficient flow to flush the debris further around the system).

I only have a low-point system drain on the return 22mm pipework, just 50cm from the boiler, and this would not necessarily flush any solid debris from the feed pipe under normal drain-down.

Based upon these assumptions / deductions; I'm going to try cutting the feed pipe and flushing the system under mains pressure from an upstairs (rad) feed pipe, in order to reverse normal direction of flow and force out any debris from parts of the system that are not on the 'path of least resistance' from normal filling point to existing drain-down (i.e. the route flushed on previous occasions). Will wait 'till the weekend, as I'm guessing this could turn out to be a big job.

I'll post again if this fixes it; or indeed plead for advice if it doesn't!

 

[OilLecky]

Oh dear John! Sounds like a good plan though. Say goodbye to the week-end! Good Luck.