hi all , I was hoping for some advice please . I recently moved into a bungalow with a 2008 ecotec plus 418 boiler . The system was using a mixture of the old underfloor microbore pipe and two rads supplied with 15mm . We never tested the boiler before we started work as we were told that one rad didn't work so we decided to replumb with new rads and the usual 22mm and 15mm pipe dropped down from the loft . When I say we I mean I used an experienced plumber . There are 6 rads in total 4 are new 1 original in the living room and one that was second hand that I had that I thought would be fine in the front bedroom. Anyway to the issue , basically the house just doesn't warm up the rads don't get proper hot only getting warm , I can force extra heat into each one by turning others off which suggests that no individual rads are blocked . The boiler cuts in rises the flow temp to 70 degrees as set then it seems to sit there for ages with the temp only ever getting to about 50 degrees at the boiler which equates to Luke warm rads and 13degrees house temperature at best . A boiler engineer suggested a power flush but I can't understand what good it would do as 95 percent of the pipe work is brand new and all but one rads gave been changed. He suggested that the boiler may be dirty but I'm confused because the water soon reaches 70 degrees momentarily and the flow pipe is too hot to hold. Can a pump become weak ? It's a grundfos 15/50 . The boiler has been down rated to 15 kw . I've tried it at different settings but it made no difference . The diverter valve clicks over and appears to work and I can feel the water switch direction when I switch to and from heating and hot water . It's on a y plan by the way . Any ideas would be greatly recieved I'm all ears . Cold ears !
New house vailant boiler
- Thread starter Sayer
- Start date
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Heat exchanger could be a bit blocked the waterways are very narrow. You only have 6 rads so set d.0 to 9. Also make sure the pump is set to number 3 and also balance the radiators. Try d.0 on 9 first and report back. Whilst in there set d.1 to 10 as well. During the heat up look at d.41 flow and d.42 return and report back the temps on this thread at say 5 minute intervals ie from cold but give the first 5 minutes at 1 minute intevals.
so
time d41 d42
1 30 10
2 32 12
3 33 12
4 36 15
5 40 20
10 50 30
15 55 45
etc etc
so
time d41 d42
1 30 10
2 32 12
3 33 12
4 36 15
5 40 20
10 50 30
15 55 45
etc etc
Pump is too small.
Ok thanks will try , also just wondered if hot water could be nicking rad heat . I think the valve on the return hot water is fully open bar 1 turn . I'm not at the bungalow tonite but I'll record the figures and post them tommorow evening . Thanks again .
Pump too small , its set to number 3 speed . What size do you suggest ?
Pump too small , its set to number 3 speed . What size do you suggest ?
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heat exchanger will be blocked. those heat exchangers get blocked very easily. a powerflush won’t clean it either. you’ll end up changing the heat exchanger i suspect
You need at least a 15-60 in there.
just do what we have said, and report back. 15/60 decent pump normally required as well but maybe see what happens with d.0 and d41 and d42 before getting too involved. What were the pipes like that got ripped out ie sludged or not what was the manifold like on the microbore. If things not too blocked up then maybe just some x800 will get things going if there is sludge in the HEx. Failing that then DS40 used carefully. But one step at a time
reallyWhats wrong with the above? We are trying to help remotely maybe we can calculate flow through the boiler if we get some data? Rather than just it is not working
Hi all , right I've done what I was asked to do and here are the results .
Set d0 to 9
Set d1 to 10
Temps were
Initial temp 12 degrees
1 34 10
2 40. 14
3 43. 17
4. 46 20
5. 48. 23
10. 57 32
15. 65 40
20. 69 46
Dial on heating is set to 70 degrees
Heating only demand no hot water calling
It definitely made a difference to the performance as the house actually got warm today , I only saw s53 pop up when I called for hot water .
Only thing was this was the first time the pump has been run for this long as the heating has been off since the old boy moved out back in march . The pump was too hot to touch way hotter than the flow going through it , is this normal ? Cheers again all for your time
Set d0 to 9
Set d1 to 10
Temps were
Initial temp 12 degrees
1 34 10
2 40. 14
3 43. 17
4. 46 20
5. 48. 23
10. 57 32
15. 65 40
20. 69 46
Dial on heating is set to 70 degrees
Heating only demand no hot water calling
It definitely made a difference to the performance as the house actually got warm today , I only saw s53 pop up when I called for hot water .
Only thing was this was the first time the pump has been run for this long as the heating has been off since the old boy moved out back in march . The pump was too hot to touch way hotter than the flow going through it , is this normal ? Cheers again all for your time
Ok so is there a gate valve on the cylinder pipework? When you called for HW had the boiler already been on ie flow temps quite high and then you turned the call for heat from the wall stat to off, so MV shut off the CH from the boiler then would have shut down as no call for heat but then the MV went to HW and the boiler would have fired at 12.6 kw regardless of d.0 this potentially may have caused the s53. Assume pump is set to 3? What cylinder do you have is it foam lagged if so what colour? As mentioned you need a 15/60 but maybe can be fettled. What is the behaviour like when the boiler eventually runs out of modulation range and shuts off whilst room stat still calling? Does it fire up again for only 30 or so seconds and get in a seemless endless loop?
Yep there is a gate valve on the return of the hot water cylinder . I left the heating on and turned the stat up on the cylinder to force it to call . Pump is set to 3 , the tank has a lime green coloured insulation , . Sorry but I'm not quite sure what modulation range is . I must admit I was so happy to get a bit of heat I didn't pay much attention to what it was doing after that . The bungalow never really reached the stat temperature but I did have stat set at 23 and the loft hatch open near the stat so it basically called all day . I could hear the boiler cutting in and out quite frequently but I think I'm right in saying the Little gas flame on the display stayed on while till flow temp went to 70 the display temp then drops for a while then it fires again back up to 70. If u tell me what specifically to look for I'm back down there tommorow and I'll have a peek . I've bought a magnaclean today with the cleaning solution . I figured it can't do any harm . Cheers scooby
you may not get an s53 in the real world as you have called for heat when there would have been latent heat in the heating coil as no draw off. Modulation is where the boiler gradually decreases its output to prevent cycling. So cylinder is fairly new but may not be quick recovery so the coil may be between 3kw and 5kw. Boiler from memory modulates down to around 5kw so may be the cause of your s.53 but you have created an artifical conditon by ramping up stat when you had a cylinder full of HW. Dont think you have a flow issue given the figures given above but as we all know these boilers like a lot of flow. See how in the first minute the temp on the flow ramped up quite quickly this is because it was running at 12.6kw for the first 50 seconds, after this has passed the boiler would have dropped down to d.0 you should have heard the fan go slower? Once like this then the flow temp has gone up in a linear fashion. Sill waiting for @AGAS to come back with why what I asked for is so crazy?
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