PeterW Posted October 3, 2018 Share Posted October 3, 2018 Valves are fine -head changes don’t need a drain down Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 4, 2018 Share Posted October 4, 2018 12 hours ago, PeterW said: Valves are fine -head changes don’t need a drain down Heads usually die because the valve bodies are gummed up and difficult to move Link to comment Share on other sites More sharing options...
Onoff Posted October 4, 2018 Author Share Posted October 4, 2018 9 hours ago, Nickfromwales said: Heads usually die because the valve bodies are gummed up and difficult to move Can the valve bodies be renovated? Thinking dunked in a tank of descaler etc. Link to comment Share on other sites More sharing options...
ProDave Posted October 4, 2018 Share Posted October 4, 2018 1 hour ago, Onoff said: Can the valve bodies be renovated? Thinking dunked in a tank of descaler etc. I "fixed" a "boiler stuck on" fault the other day. It was the HW motorised valve seized. Removing the actuator and the controls worked and the boiler shut off correctly. Initially the valve was stuck solid but a pair of mole grips got it turning and after several full revolutions it was turning freely. Put the actuator back and it all worked fine. I did warn him if it seizes again he will need a plumber to replace the valve body. I wonder if it was just gummed up with carp and rotating it several times further than the actuator turned it cleared all the debris. for now. Link to comment Share on other sites More sharing options...
dpmiller Posted October 4, 2018 Share Posted October 4, 2018 descaler won't fix a leaking seal. Link to comment Share on other sites More sharing options...
Onoff Posted October 7, 2018 Author Share Posted October 7, 2018 Just got a new, Honeywell V4073A1088 mid position valve. Paid £60. Link to comment Share on other sites More sharing options...
Onoff Posted October 10, 2018 Author Share Posted October 10, 2018 I'm assuming the valve body size will be different between the Honeywell and existing Tower 3-port valve? If not then can I leave in situ the existing nuts/olives on the pipe and connect straight to the Honeywell with copious amounts of Jet Blue Plus? If I have to then vague memories of replacing one years back and without the proper olive removal tool getting the old 28mm olive off without damaging the pipe was a pig. A hacksaw blade did it eventually I seem to recall. Going to source a couple of 22mm 2-ports (likely Drayton) and do all 3 valves in one hit. Again, hoping brass body size is the same as the Tower ones! Link to comment Share on other sites More sharing options...
PeterW Posted October 10, 2018 Share Posted October 10, 2018 Valve bodies are pretty standard - you like Jet Blue, I hate it but use what you know... Link to comment Share on other sites More sharing options...
Onoff Posted October 10, 2018 Author Share Posted October 10, 2018 22 minutes ago, PeterW said: Valve bodies are pretty standard - you like Jet Blue, I hate it but use what you know... Ta.....so can I keep the old olive? Wouldn't have had anything on there previous. Figuring some "lube" would enable me to nip it up that bit extra. Link to comment Share on other sites More sharing options...
PeterW Posted October 10, 2018 Share Posted October 10, 2018 Clean it all up well and it may be OK. 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted October 10, 2018 Share Posted October 10, 2018 The main "gotcha" I've encountered is when a manufacturer decides to use a finer thread than standard. I got caught out replacing a pressure reducing valve by this; one had a standard thread and accepted any normal 22mm compression nut, one had a fine thread that didn't, so it meant pulling the olives off. Perhaps worth trying to have a look before you start, so if the threads do look different you'll be prepared (I wasn't, and I wasted a lot of time doing what should have been a simple job). Link to comment Share on other sites More sharing options...
Onoff Posted November 7, 2018 Author Share Posted November 7, 2018 Decided to as I'm draining down to replace the leaking Tower 3 port 28mm that I'll replace both 2-ports, again Tower brand as one looks a bit suspect i.e. stained. And at the same time give the whole CH system a bit of a clean etc. Deffo got some issues. For instance the system was calling for HW yet the upstairs rads were getting warm the other night! Only guess is the old Tower valves are letting by. I've procured a new Honeywell 28mm 3 port (£60) and two Honeywell 22mm 2 ports (£40 ea). Hoping then: 1) The brass bodies are interchangeable and I don't have to shorten lengthen pipes. 2) That I don't have to remove any olives i.e. reuse the old. With lashings of Jet Blue I reckon they might do up a bit tighter than before. 3) A week maybe two before I do this, should I had some sort of system cleaner to stir things up etc? Vaguely remember adding something via the radiator years ago... 4) Should I think about some sort of Magnaclean thing if so what's good? 5) The upstairs flow / return system (5 rads) doesn't have a drain cock anywhere, add one? 6) The downstairs, ancient single pipe system does have a drain cock that I added. Permanently in place I've a hose attached that runs under the suspended ground floor, through the wall then across the path to the flower bed. 7) What additive should I add upon completion? Any pointers appreciated, anything I've missed? Link to comment Share on other sites More sharing options...
ProDave Posted November 7, 2018 Share Posted November 7, 2018 Before you tighten up, have a look that the olive is touching it's "cone" in the fitting. What can happen sometimes is the pipe is pushed in as far as it will go then tightened. Change the fitting for another, and the new fitting does not have as much room for the pipe, so the olive (already compressed and stuck to the pipe) does not seat in it's cone as the pipe has bottomed out in the fitting first. If you encounter that, shorten the pipe a bit. You learn this when no matter how tight you tighten it, it won't seal. 1 Link to comment Share on other sites More sharing options...
Onoff Posted November 7, 2018 Author Share Posted November 7, 2018 19 minutes ago, ProDave said: Before you tighten up, have a look that the olive is touching it's "cone" in the fitting. What can happen sometimes is the pipe is pushed in as far as it will go then tightened. Change the fitting for another, and the new fitting does not have as much room for the pipe, so the olive (already compressed and stuck to the pipe) does not seat in it's cone as the pipe has bottomed out in the fitting first. If you encounter that, shorten the pipe a bit. You learn this when no matter how tight you tighten it, it won't seal. Top tips there, thanks. Pretty sure I've changed one of them in the past but fitted like for like i.e Tower. No idea now which one(s)! Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 7, 2018 Share Posted November 7, 2018 A few turns of ptfe over a heavily ( previously ) crushed olive makes for a good seal. Link to comment Share on other sites More sharing options...
Onoff Posted November 18, 2018 Author Share Posted November 18, 2018 Getting myself in a tizzy here about what's doing what but I've got a heating circuit coming on as in downstairs rads warm when the controls are only calling for DHW. The 2 2-ports are operated by a contactor each and they're NOT calling the valve. That must mean not only is the 3-port letting by but the downstairs 2-port also. Both show heavy 'ish leaking under the covers. Also, can't remember which way round but think the downstairs rads get warm when only upstairs is calling. That would fit the symptoms if the downstairs 2-port is letting by. Would ask my boiler guru mate but he's not well. I've got Honeywell replacements, best man up and do it! Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 18, 2018 Share Posted November 18, 2018 Why don’t you just go to 3x 2-port? You won’t get guaranteed pump overrun with that arrangement anyway. Hace you ever had the boiler overheat stat pop and you’ve had to manually reset it ?( boiler kettled ). Link to comment Share on other sites More sharing options...
Onoff Posted November 18, 2018 Author Share Posted November 18, 2018 (edited) 26 minutes ago, Nickfromwales said: Why don’t you just go to 3x 2-port? You won’t get guaranteed pump overrun with that arrangement anyway. Hace you ever had the boiler overheat stat pop and you’ve had to manually reset it ?( boiler kettled ). I've bought the bloody 3-port already! You mean like this? Plus I don't do well doing things on the fly, I have to consider & plan etc. Not the thing when the house is freezing and it needs to be up and running asap. Boiler stat tripping, no don't think so. Edited November 18, 2018 by Onoff Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 19, 2018 Share Posted November 19, 2018 Yup. Like that. Much simpler to control. Does your boiler do pump overrun ? Link to comment Share on other sites More sharing options...
Onoff Posted November 19, 2018 Author Share Posted November 19, 2018 3 hours ago, Nickfromwales said: Yup. Like that. Much simpler to control. Does your boiler do pump overrun ? You asked before and I don't know what that is... Link to comment Share on other sites More sharing options...
Ed Davies Posted November 19, 2018 Share Posted November 19, 2018 Pump keeps running for a few minutes after the boiler stops to make use of the heat remaining in the boiler. Otherwise it just goes to waste (e.g., for an outdoor boiler) or waits and gets used when the boiler next runs. E.g., for the oil boiler in the house I'm renting when the thermostat calls for heat the S-plan wiring sends power to the pump and boiler but the boiler is already hot enough from the last run so doesn't fire up for a minute or two. The thermostat called for heat at just before 10:53. The power consumption increased as the pump started. and about 1.5 minutes later the water got to the radiator in my study and its temperature started to increase and the temperature sensor there began to notice. At 10:55 enough hot water in the boiler had been replaced by cold that the boiler started up further increasing the power consumption. It'd be more efficient for this extra pump run to happen at the end of the cycle but that'd be a bit more complicated with simple S-plan wiring where just the valve-motor current goes through the thermostat. Problem is, if the boiler controller is controlling the pump and does the overrun but only gets a signal that the call for heat has ceased because the zone valves have closed it results in the pump pushing against closed valves. Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 19, 2018 Share Posted November 19, 2018 That’s an efficient explanation but the textbook requirement for boiler overrun is other. A sealed and pressurised system boiler can shut off at full heat with no detrimental effect. However, if the same happens in a ‘heat only’ boiler then the heat exchanger instantly super heats the water to the point that the overheat stat nuisance activates, requiring manual reset. Therfore the overrun is, in old money, to stop the residual heat in the boiler kettling the water and causing lock out. That’s why you don’t see 2-port or diverter valves on a heat only install, instead you have the mid-position valve which never closes 100% shut like the others do. So, to answer the question about overrun on your boiler setup, simply allow the heating to come on for 10 mins or so, and before it gets a chance to achieve the set point temp of the boiler controls, you shut the heating controls off ( not the power ) and see if the pump instantly goes off. If it is energised for a couple of minutes after call for heat has gone then you have a pump overrun arrangement and you can’t go all 2-port. However #2, if your overrun goes into heating your stuffed anyway as the 2 x 2-ports will close ? and at that stage you’d need a T before the 2x 2-ports that goes into an automatic bypass valve and back to return. Clear as mud lol. ? Link to comment Share on other sites More sharing options...
Ed Davies Posted November 19, 2018 Share Posted November 19, 2018 Isn't another way to tell if it could do overrun to look at the wiring for the pump? If it comes off the boiler control board then it could be an overrun one so you have to do the experiment @Nickfromwales suggests. If the boiler controller doesn't have a pump output, so the pump's wired straight off the wiring centre, then I think it can't be an overrun one? The pump for the non-system (vented) oil boiler here is wired direct from the wiring centre (i.e., in series with the switched outputs of the zone valves and in parallel with the boiler itself) even though it's actually inside the boiler case. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 19, 2018 Share Posted November 19, 2018 By the same token, one of the early problems with the old Sunamp PV was that the pump over run time (essential to stop the water heater tube from over-heating from heat soak and tripping the over-temp switch) was too short. That system used to run at around 65 deg C or so normally, but with the short pump over run time the water heater tube would trip a 90 deg C resettable switch a minute or two after the heater shut down. Link to comment Share on other sites More sharing options...
Nickfromwales Posted November 19, 2018 Share Posted November 19, 2018 43 minutes ago, Ed Davies said: Isn't another way to tell if it could do overrun to look at the wiring for the pump? If it comes off the boiler control board then it could be an overrun one so you have to do the experiment @Nickfromwales suggests. If the boiler controller doesn't have a pump output, so the pump's wired straight off the wiring centre, then I think it can't be an overrun one? Given the multitude of wiring sins I’ve come across in my time, in a nutshell, no.? Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now