cwr Posted February 11, 2022 Share Posted February 11, 2022 Hi folks Any recommendations for 22mm 2 port valves for use in a fairly standard S plan heating system? Eg, any particular makes to go to, or avoid? Thanks Link to comment Share on other sites More sharing options...
Onoff Posted February 11, 2022 Share Posted February 11, 2022 Honeywell imho. 1 Link to comment Share on other sites More sharing options...
Radian Posted February 11, 2022 Share Posted February 11, 2022 I would love to find a decent off-the-shelf product , but concluded long ago that there is no such thing. My lowly opinion is largely based on the fact that they all appear to be copies of an ancient, bodged-together, low-tech design that gobbles electrical power like it was too cheap to bill for (a dream that never actually materialised in the nuclear age). Don't let me put you off though. @Onoff's favourite Honeywell is at the more expensive end of the market so you would certainly deserve to get a better lifespan out of it but I wouldn't count on it. Just keep an eye on their vampire power... when you find they're too hot to touch you might assume it's because of the temperature of the water flowing through them. It isn't. Link to comment Share on other sites More sharing options...
ProDave Posted February 11, 2022 Share Posted February 11, 2022 From experience, Honeywell has been the most reliable, Danfoss the least. But regardless of which make you choose, 2 port valves and S plan are ALL infinitely more reliable than that utter bodge of the 3 port mid position valve and Y plan. THAT is what you want to avoid. Link to comment Share on other sites More sharing options...
Onoff Posted February 11, 2022 Share Posted February 11, 2022 I'd been through a few Tower/Grasslin ones that had died. Tbh that may have been through a system not being cleaned since it went in circa 1953. That and the fact my technique for compression fixings hadn't evolved. I now use Jet Blue Plus on compression exclusively. No PTFE. So far, great. Is there a case to try and get one where you can change the actuator / motor for a "universal" one without having to touch the plumbing? Link to comment Share on other sites More sharing options...
ProDave Posted February 11, 2022 Share Posted February 11, 2022 4 minutes ago, Onoff said: Is there a case to try and get one where you can change the actuator / motor for a "universal" one without having to touch the plumbing? You can remove the Honeywell, Tower and Danfoss actuators from the valve body without draining down. You can even buy new motors and many other parts for them. It is the microswitches that seem to be the weak link on Danfoss heads and they are not easy to change. A minor irritation is a while back Honeywell changed the physical interface between actuator and valve body. I found out embarrassingly when I tried to replace a failed actuator head to find it did not fit the old valve body. Link to comment Share on other sites More sharing options...
Radian Posted February 11, 2022 Share Posted February 11, 2022 1 minute ago, Onoff said: Is there a case to try and get one where you can change the actuator / motor for a "universal" one without having to touch the plumbing? At the very least, put in a pair of isolators either side. They'll come in handy in a few years time. Link to comment Share on other sites More sharing options...
PeterW Posted February 11, 2022 Share Posted February 11, 2022 Seen a few of these fitted and local guys swear by them as they seem to last https://www.bes.co.uk/horstmann-z222-motorised-zone-valve-2-port-22mm-21057 Link to comment Share on other sites More sharing options...
Radian Posted February 11, 2022 Share Posted February 11, 2022 5 minutes ago, PeterW said: Seen a few of these fitted and local guys swear by them as they seem to last https://www.bes.co.uk/horstmann-z222-motorised-zone-valve-2-port-22mm-21057 Quote Powerful 'f' class synchron motor Class F motor insulation is supposed to be good for 155 Degrees C so that's something to its credit. But I'm going to keep banging on about how much of the heat they generate is down to their electrical power consumption. Funny how that figure is seldom advertised. 1 Link to comment Share on other sites More sharing options...
Onoff Posted February 11, 2022 Share Posted February 11, 2022 17 minutes ago, ProDave said: It is the microswitches that seem to be the weak link on Danfoss heads and they are not easy to change. They were a doddle to change tbh on the Tower valves. Link to comment Share on other sites More sharing options...
PeterW Posted February 11, 2022 Share Posted February 11, 2022 22 minutes ago, Radian said: But I'm going to keep banging on about how much of the heat they generate is down to their electrical power consumption. Funny how that figure is seldom advertised. Horstmann is 5W according to the data sheet so 6 hours day / 120 heating days a year that’s 3.6kWh… or 75p 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 12, 2022 Share Posted February 12, 2022 Honeywell for me. Used them since day 1 and never had any issues. Reliable and robust. Industry standard afaic. Link to comment Share on other sites More sharing options...
Radian Posted February 12, 2022 Share Posted February 12, 2022 10 hours ago, PeterW said: Horstmann is 5W according to the data sheet so 6 hours day / 120 heating days a year that’s 3.6kWh… or 75p Are you just assumng the motor isn't energised in both valve positions? The several different ones I've used over the years have all run the motor to stall in both positions, with the microswitch switching in a current limiting resistor to prevent the motor winding burning out. Overall roughly the same power is dissipated 24/7. This is what gives rise to their inherent unreliability. Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 12, 2022 Share Posted February 12, 2022 59 minutes ago, Radian said: Are you just assumng the motor isn't energised in both valve positions? The several different ones I've used over the years have all run the motor to stall in both positions, with the microswitch switching in a current limiting resistor to prevent the motor winding burning out. Overall roughly the same power is dissipated 24/7. This is what gives rise to their inherent unreliability. They only get energised to change state, and that stores energy in a spring to return to the parked position ( Honeywell do anyhoo ) unassisted by electrical input. Your above statement is too general, eg “several different ones”. Which ones? State the valve type and model of the ones that consumes power 24/7/365 please. I’ve got Honeywell ZV’s that have been in for 20 years now and fitted for people I see frequently. Link to comment Share on other sites More sharing options...
ProDave Posted February 12, 2022 Share Posted February 12, 2022 And most makes energise the motor to open, then switch a resistor or something similar to keep the motor energised at a lower power and stalled to keep it open. The mid position valves insert a diode in line and stall the motor with DC to hold the mid position. If the valve is inside the house that 3.6kWh per year of energy is not "wasted" but used to heat the house just a little. Link to comment Share on other sites More sharing options...
PeterW Posted February 12, 2022 Share Posted February 12, 2022 1 hour ago, Radian said: Are you just assumng the motor isn't energised in both valve positions? The several different ones I've used over the years have all run the motor to stall in both positions, with the microswitch switching in a current limiting resistor to prevent the motor winding burning out. Overall roughly the same power is dissipated 24/7. This is what gives rise to their inherent unreliability. I wouldn’t use Wikipedia as a source of truth with a sweeping statement like that in it ! And the Horstmann ones are spring return as are most of the single zone valves. Ones that stall both ways are usually the mid position 3 way valves which are the work of the devil - I only use zone or diverter which both have spring return. Link to comment Share on other sites More sharing options...
Radian Posted February 12, 2022 Share Posted February 12, 2022 Pardon me. Recently I've got my head too full of DC actuators, it's a synchronous motor so only goes one way without extra effort. Can't recall if the spring return makes it NO or NC? Link to comment Share on other sites More sharing options...
PeterW Posted February 12, 2022 Share Posted February 12, 2022 All zone valves tend to be NC - Honeywell do an NO but it’s not the head that makes it that it is the valve body that has different stops inside it. Link to comment Share on other sites More sharing options...
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