MtB Posted September 28, 2019 Report Share Posted September 28, 2019 15 minutes ago, Chewbacka said: Not sure if this has been considered, but is the pump capacity too small for the heater unit?? Is the pump not integrated within the heater unit? Link to comment Share on other sites More sharing options...
chevron Posted September 28, 2019 Report Share Posted September 28, 2019 Pumps fastened to unit connected by short rubber pipe,I have wondered are coolant pipes the right way round at unit is it drawing the coolant from the radiator circuit and not direct from the header tank ? Link to comment Share on other sites More sharing options...
Nobag Posted September 28, 2019 Report Share Posted September 28, 2019 (edited) 2 hours ago, Mike the Boilerman said: How does this not present exactly the same difficulty in priming the non-self-priming water circulator? All i can say is that i used this method to test mine before i fitted it to the boat. There are many video's on YouTube showing people testing these units. Edited September 28, 2019 by Nobag To add YouTube link 1 Link to comment Share on other sites More sharing options...
Chewbacka Posted September 28, 2019 Report Share Posted September 28, 2019 27 minutes ago, Mike the Boilerman said: Is the pump not integrated within the heater unit? Some units (certainly the thermo top evo) have a separate pump. Even if the pump came with the heater it may be worn and not have enough capacity if the op plumbing has too much resistance. Link to comment Share on other sites More sharing options...
Kelbs Posted September 28, 2019 Author Report Share Posted September 28, 2019 So the pump is attached to the unit, as in the picture. I don't think it's a Webasto pump, as the fuel pump isn't and the unit is a recon so I wouldn't be surprised if the parts were cheap replacements. 31 minutes ago, chevron said: Pumps fastened to unit connected by short rubber pipe,I have wondered are coolant pipes the right way round at unit is it drawing the coolant from the radiator circuit and not direct from the header tank ? The return pipe is coming directly from the header tank into the Webasto unit, via two elbow bends. The pipes are most definitely the right way around, as in the flow is the flow and the return is the return. Link to comment Share on other sites More sharing options...
Tash and Bex Posted September 28, 2019 Report Share Posted September 28, 2019 Despite concerns about priming, I've had webasto's warming paddling pools up, warming crates of water for a camping shower up, give it a shot Link to comment Share on other sites More sharing options...
Cheshire cat Posted September 28, 2019 Report Share Posted September 28, 2019 It looks to me like the OP needs to test it as per the video. If it works OK then it must be the plumbing. As long as the bucket is high enough and the hoses are primed air locks can be eliminated. Link to comment Share on other sites More sharing options...
Tony Brooks Posted September 28, 2019 Report Share Posted September 28, 2019 7 hours ago, Chewbacka said: Not sure if this has been considered, but is the pump capacity too small for the heater unit?? Or a major restriction in the pipework somewhere e.g. rad valves turned off or set too far closed,TVR (mentioned before), If one is fitted a heat & water or water only valve wrongly connected or set but without a detailed diagram we have no idea what the OP has so it is all guess work.. Link to comment Share on other sites More sharing options...
Kelbs Posted September 28, 2019 Author Report Share Posted September 28, 2019 58 minutes ago, Tony Brooks said: Or a major restriction in the pipework somewhere e.g. rad valves turned off or set too far closed,TVR (mentioned before), If one is fitted a heat & water or water only valve wrongly connected or set but without a detailed diagram we have no idea what the OP has so it is all guess work.. I have flow and return pipes, 22mm, which run down the length of the boat, the rads are all teed off these pipes with 15mm pipe. All the valves are open and the TRV is still fitted but I can't see why it would be a problem on this system as it is teed off the main feeds. Link to comment Share on other sites More sharing options...
Tony Brooks Posted September 28, 2019 Report Share Posted September 28, 2019 1 hour ago, Kelbs said: I have flow and return pipes, 22mm, which run down the length of the boat, the rads are all teed off these pipes with 15mm pipe. All the valves are open and the TRV is still fitted but I can't see why it would be a problem on this system as it is teed off the main feeds. I agree with that. However you now say 22mm where as a few days ago you were talking abut 28mm so its no wonder I am having problems. I do wonder if by some chance the impeller has fallen off the motor spindle but the you say that upon shutdown it circulates cold water (not sure how you know that through). this is no more than a faint possibility. Link to comment Share on other sites More sharing options...
Kelbs Posted September 28, 2019 Author Report Share Posted September 28, 2019 33 minutes ago, Tony Brooks said: I agree with that. However you now say 22mm where as a few days ago you were talking abut 28mm so its no wonder I am having problems. I do wonder if by some chance the impeller has fallen off the motor spindle but the you say that upon shutdown it circulates cold water (not sure how you know that through). this is no more than a faint possibility. The 28mm pipe is the black flexiable hose running from the webasto to the bulkhead, 28mm external, 19mm internal. After the bulkhead the 22mm pipe starts. I'm assuming that the pump starts circulating the water because within two minutes of the shut down cycle the webasto unit and the black hose go from being too hot to touch to being room temperature again. I thought this was due to tje pump circulating.. It's all terribly confusing to be honest. Link to comment Share on other sites More sharing options...
Nobag Posted September 28, 2019 Report Share Posted September 28, 2019 Close both radiator valves on each one to keep the antifreeze/water in, drain the 22mm loop into a container for reuse. Then do the bucket test from YouTube video. At least you can rule out a faulty heater or not. Link to comment Share on other sites More sharing options...
Kelbs Posted September 29, 2019 Author Report Share Posted September 29, 2019 Ok, I've made a bit of progress. Finally. I connected the circulation pump directly to a battery and it pumped water around freely. I then turned the webasto unit on and ran that, with the pump still on the seperate feed, for about 5 minutes and have managed to get hot water into all of the rads. This to me is a huge step in solving the issue here. Now, does anyone know what this may be? Link to comment Share on other sites More sharing options...
Nobag Posted September 29, 2019 Report Share Posted September 29, 2019 11 minutes ago, Kelbs said: Ok, I've made a bit of progress. Finally. I connected the circulation pump directly to a battery and it pumped water around freely. I then turned the webasto unit on and ran that, with the pump still on the seperate feed, for about 5 minutes and have managed to get hot water into all of the rads. This to me is a huge step in solving the issue here. Now, does anyone know what this may be? If you connect the pump back up to the boiler and it still does not work properly, then I would think the PCB is faulty. Link to comment Share on other sites More sharing options...
Kelbs Posted September 29, 2019 Author Report Share Posted September 29, 2019 Still overheats when plugged back together. Pointing towards a manufacturing problem. What a long process of elimination! Link to comment Share on other sites More sharing options...
Kelbs Posted October 1, 2019 Author Report Share Posted October 1, 2019 Just for the record, I've got the circulation pump connected to the 12v fuse board and wired completely separate. This allows me to use the Webasto as a functioning heater. It's only a temp fix until the refurbisher is back off his holiday so he can send me a new wiring loom (he thinks this is the issue). Will update once the new loom turns up. 1 Link to comment Share on other sites More sharing options...
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