Paul Deslandes Posted January 2, 2013 Share Posted January 2, 2013 Home heating system packed up a few weeks ago. 3-way motorised valve had been making a noise and then gave up. Took off head and found teeth were stripped on motor drive. Valve spindle seemed free so replaced head. OK for a couple of weeks and then head stopped running, assumed faulty so replaced by shop. New one again ok for a month and now playing up again. Removed head from valve body but left wired up. All working ok although obviously the valve isn't controlling water flow (pumped HW and CH). My assumption is that the valve itself must be knackered, even though the spindle seems to turn. The amount of spindle rotation is however very limited, I would guess about 20deg either way from central, if that. Obvious answer is go and by a complete replacement unit, drain down and fit. Spare innards are available but I don't want to take it all apart to repair and find I have to get a complete new one anyway. Anyone know the valve innards of these things. (not the head, I think I've got that sussed). Link to comment Share on other sites More sharing options...
andy_h Posted January 2, 2013 Share Posted January 2, 2013 I think they are just a valve (butterfly spindle type) and not worth trying to fix. Either something is broken (needs to be removed to fix anyway) or your pipes are chocked up with scale etc. I'd suggest remove and replace with new, but I'm sure a friendly plumber will be along shortly Link to comment Share on other sites More sharing options...
charlie_pank Posted January 2, 2013 Share Posted January 2, 2013 Hi Paul, I spent quite a lot of time last year chasing faults around my central heating/hot water systems. Including swapping out the heads of the valves you're talking about, and replacing the expansion vessel. After going through the hassle of draining and refilling, I decided to try out the freeze sprays instead. I have to say that they were excellent and saved me a lot of hassle. They're well priced - not quite expensive enough to stop you buying them and draining the system instead, but I'd use them again. It should be a doddle to swap over the valve after freezing. Edited by - charlie_pank on 2 Jan 2013 15:14:45 Link to comment Share on other sites More sharing options...
Area Representative bluenose Posted January 2, 2013 Area Representative Share Posted January 2, 2013 Why oh why do plumbers not fit isolation valves either side of central heating 2/3 way valves? Nick Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 2, 2013 Author Share Posted January 2, 2013 Cost I expect. In the absence of any advice to the contrary, I've bought a complete new valve although I'm not entirely convinced yet as the range of rotation of the spindle in the new one seems to be about the same. It may be that the old valve spindle is jamming when its hot so that the head can't turn it fully. Anyway, SWMBO is fed up with the contents of the airing cupboard being piled up on the landing floor so its going to have to be changed. The pipes are 28mm and I'm not confident enough with freezer at that pipe size although I have used it with 15 and 22mm. The consequences of it failing are too awful to contemplate so I'm going to drain down far enough to get the valve out. I shall probably be spending the next week trying to get rid of airlocks. Any clues on how to jack up the front of the house, like bleeding a 7 😬 Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted January 2, 2013 Member Share Posted January 2, 2013 Quoting bluenose: Why oh why do plumbers not fit isolation valves either side of central heating 2/3 way valves?Yes. And isolators for the hot and cold feeds into each room. Jonathan Link to comment Share on other sites More sharing options...
Area Representative bluenose Posted January 2, 2013 Area Representative Share Posted January 2, 2013 We have had a sealed pressurised system for the last 5 years and that seems to have sorted out the airlocks. Nick Link to comment Share on other sites More sharing options...
Area Representative bluenose Posted January 2, 2013 Area Representative Share Posted January 2, 2013 Oops Edited by - bluenose on 2 Jan 2013 21:02:40 Link to comment Share on other sites More sharing options...
Martin J Posted January 2, 2013 Share Posted January 2, 2013 I have replaced many motorized valves over the years (probably thousands 😳) if you do get stuck & need advice, feel free to ask..... Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 7, 2013 Author Share Posted January 7, 2013 finally got around to changing the complete valve this morning. It looks as though the rubber ball has swollen slightly over the 20 plus years its been in there and the motor couldn't turn the spindle far enough to activate the second microswitch. So I have a spare three-way head unit if anyone's short. Thanks for the advice. Link to comment Share on other sites More sharing options...
Martin J Posted January 7, 2013 Share Posted January 7, 2013 well done the swollen ball 😳 is often how they fail, sometimes chemicals added to the system cause it to happen. Honeywell do a ball & plate referb kit to save changing the whole 3 port body, which saves a lot of work sometimes. In the vast majority of cases I do this without draining the system, just "bung" the header tank. I don't often have a disaster. Link to comment Share on other sites More sharing options...
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