edwardatherton Posted November 20, 2007 Share Posted November 20, 2007 This morning we had hot water but all the radiators were cold. This evening it is the same. From looking at a few web pages it means the pump that circulates the water has packed up. It is a Grundfos Selectric 15/50 which looks to be about £60 from a quick Google search. How can I test if this is right? The big round red bit does not appear to be doing anything at all, but there is also a square metal bit above it. What's that? Any help much appreciated as it is a tad cold at the moment. Personally I would just put the heater on in the garage and continue work on the trailer for a few nights and worry about plumbing once the Sankey is roadworthy, but SWMBO won't let me... Quote Link to comment Share on other sites More sharing options...
rtbarton Posted November 20, 2007 Share Posted November 20, 2007 Remove screw in the middle of the pump and you should expose the end of the shaft. This should turn freely with a screwdriver, and should be turning in the direction on the arrow when the pump is on. If it's jammed a twist should free it off. The device above looks like a motorised valve, water goes from the pump then to one of the 'arm' depending on the position of the motor. This valve could control the water/heating, or upstairs/downstairs - it all depends on the guy who designed the system. Can you trace the two pipes coming out of the sides of the valve? Quote Link to comment Share on other sites More sharing options...
Fatboy Posted November 20, 2007 Share Posted November 20, 2007 When the central heating is "on", you should be able to hear the pump turning... a quiet shwooshing sound. If you can't, it may be kaput but it would be worth putting a megger on it to make sure it is getting power. If it is pumping and there is hot water up to it, then it is the electric flow control valve above that is goosed. You can just replace the elctic actuator without having to break into the water system. As a temp fix / trial, remove the electric actuator and turn the valve "on" with a shifter. If the central heating then works, its the actuator. Quote Link to comment Share on other sites More sharing options...
leeds Posted November 20, 2007 Share Posted November 20, 2007 IIRC there should be a valve either side of the pump, (immeadiately next to pump) which enables the pump to be replaced easily without draining the system. There is a gate valve below the pump but I can't see a valve above the pump. If there is no valve immeadiately above pump, you could use a freezer spray above the pump wich will enable you to change pump without part draining system HTH Regards Leeds Quote Link to comment Share on other sites More sharing options...
rtbarton Posted November 20, 2007 Share Posted November 20, 2007 The motorised valve may have an "off" position? Quote Link to comment Share on other sites More sharing options...
jamesm Posted November 20, 2007 Share Posted November 20, 2007 You can just replace the elctic actuator without having to break into the water system. As a temp fix / trial, remove the electric actuator and turn the valve "on" with a shifter. If the central heating then works, its the actuator. Be careful when you're undoing the screws on the actuator - mine turned out not to be separate from the water system and I got squirted with rusty water! If you examine the ends of the motorised valve you'll probably find there's a lever for operating it manually, but it may only work the valve in one direction. If that's the case, you can help the actuator do it's job by taking the tin cover off and pushing the gears round with a screwdriver - I have to do this every year to get the system going after summer. Unfortunately, it hasn't worked too well this time and it looks like a new valve is required. Quote Link to comment Share on other sites More sharing options...
mpb Posted November 20, 2007 Share Posted November 20, 2007 If the pump isn't turning, a couple of sharp taps with a hammer may help. I've had to do this to a couple of pumps. Quote Link to comment Share on other sites More sharing options...
Milemarker Type S Posted November 20, 2007 Share Posted November 20, 2007 If the pump isn't turning, a couple of sharp taps with a hammer may help. I've had to do this to a couple of pumps. As above, try removing the screw from the end and turning with a screwdriver and if no sucess then give it a good sharp tw@ting with a hammer... The pump has probably siezed up over the summer when you were not using your heating. Shrek Quote Link to comment Share on other sites More sharing options...
rod Posted November 21, 2007 Share Posted November 21, 2007 The box above the pump is a motorised zone valve. In your set-up this controls whether the boiler is heating the hot water in the cylinder or sending it to he radiators, or doing both. If you are getting heat in the pipe that runs from the zone valve in to the cylinder (front one in pic) and no heat to the pipe which runs out the zone valve then the valve is knackered. Some valves have the option of a little slider on them allowing you to move the valve to a manual fully open position allowing you to have heat and hot water while you sort a new one out if this is the problem. If there is heat in the pipe coming from the back of the zone valve and going down through the floor to the rads then it is probably a knackered pump - although i would expect heat to some rads or certainly to the pipework beneath some radiators due to the gravity effect - ie hot water from the boiler pushing the cold round the system. Why is it it takes 3 paras to explain something i'd be able to do in 5 seconds ..... Quote Link to comment Share on other sites More sharing options...
Milemarker Type S Posted November 21, 2007 Share Posted November 21, 2007 And the valve above is a three way valve that diverts the flow of hot water depending wheter or not you need hot water, or central heating or indeed both. It will contain a syncronous motor which can easily over heat- especially if Doris has stacked bedding and towels all over it... If this is the fault you may be able to replace just the motor or indeed the motor and housing without actually having to take the actual brass valve section off the pipework.... Shrek Quote Link to comment Share on other sites More sharing options...
paintman Posted November 21, 2007 Share Posted November 21, 2007 I also have to do the annual 'remove screw cover in the middle of the pump & turn with a screwdriver' trick on the pump. It then works fine. Until the start of the following winter! Once you have removed the screw cover you will see a slot in the end of the shaft. Turn the system on & it should spin round. If it does then the pump is OK. If it doesn't, turn with a screwdriver. If that doesn't work then tap the pump. If that doesn't work then, after checking that the system was turned on & power is going to the pump, the pump is probably history. BUT. If the water is heating OK & you are not heating the water overnight with an immersion heater then it suggests that the gate valve is the likely culprit. Quote Link to comment Share on other sites More sharing options...
edwardatherton Posted November 21, 2007 Author Share Posted November 21, 2007 Thanks very much everyone - it is indeeed the motor on the diverter valve. The motor spins fine. I found a little manual switch on the back of the valve so the rads now work, and as luck would have it it is less than £14 from onlineplumbingsupplies.co.uk. The motor can be replaced without the valve, apparently! I don't think SWMBO was expecting much of a result - she didn't look impressed when I said I had put a message on a LR forum regarding central heating! Quote Link to comment Share on other sites More sharing options...
sgnas Posted November 21, 2007 Share Posted November 21, 2007 Now thank you lucky stars that whoever installed all that left it reasonably accessible. In my current house the 3 way valve is installed at the back of the cupboard, behind several other pipes and (piece de resistance) facing the back of the cupboard In a previous house the pump was installed horizontally at the lowest point in the system. A prime no-no and it got silted up! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.