Tasemu

I'll have a look when I get home and report back with all detail I can find for all questions

Going to double check the eberspacher after work today and see how it heats up (duff meaning broken?). Not sure what cold burning diesel is. Also not sure if you're being sarcastic about the nice engine or not haha... Is it really?

I heard from the owner that the engine is raw water cooled, somehow that has to do with it. It's a 1973 SABB 2HG.

Our engine is not connected to the calorifier though

Righto, i'm going to run it again today without the engine running and see how hot it gets ? Maybe the eberspacher has died

This is mostly just a curiosity and was wondering if there was a good reason why this happens. We were running our engine (not connected to the calorifier) to charge our batteries. I figured I might as well run the eberspacher water heater at the same to get some hot water. After running the eberspacher for an hour i noticed the water was warm at best. I've run it in the past without the engine going and it has got scalding hot, so i'm wonder why it would not be working properly when the engine was going. It appeared to complete the hour run too. Cheers for any thoughts and/or advice!

Cheers, i do have a manual switch installed now, was considering reinstalling it so i have both, convenience and backup manual. but good point, i can just turn it on and chill

Possibly, now i have noticed a small led in the wall switch which is also fading out after a few seconds, its very very dim. I'm going to replace the battery and see

You heard it here first haha

Yep i reckon so, its a remote button on the wall, my new switch is right next to the pump, but just a temp measure, but if it dies again i have a backup switch

I also thought it might be the switch, i found a "fuse box" that when opened showed a lot of chips and an arial instead of fuses. This got me thinking that the switch on the wall may perhaps be a remote switch to this box... And a remote switch must need a battery. When i opened up the wall switch, bam, there was a a27 battery that is flat as a pancake! I've not put a simple rocker switch rated at 10 amps in the positive line to the pump and removed the remote box. Soon i'll try and find a new a27 battery and rig it back up. but I'm happy to have a working pump now pics:

I've mounted the new whale gulper level on the floor, and wired it all up. The exact same issue is happening with the new pump. I hold the switch on the wall and the pump cuts out after a few seconds. ?

Bidding on a whale gulper now, come on cheapo ebay you can do it! Still gonna have to somehow get this pump off the mounts... Maybe JD will help.

That may be difficult, i cannot get the motor off its mounting brackets, those screws are in tight as hell.

Ok so i just disconnected the bath to the pump and ran the pump, it still cuts out after 5 seconds, and last less time each subsequent try. For example: press and hold: lasts 5 seconds press and hold: lasts 3 seconds press and hold: lasts 1 second press and half: lasts half a second leave for a while press and hold: lasts 5 seconds etc

I almost did on my own... but only stopped because i couldn't fit my head under the bath to reach it hahaha

Excellent! I had no idea, i'll run it in a moment and report back

Just got back to the pc after getting to work, here is what I did and what I found. What I did: 1: scooped out the bath water 2: unplugged each hose from the pump 3: couldnt unscrew the pump from the floor ( they were in very tight!) 4: took apart the diaphragm with it still mounted 5: cleaned what i could, it was in pretty good condition with only some scale on the inside of the cap 6: blew out the hose to the hull, felt like something shot out the end... maybe 7: put it all back together 8: slight improvement but pump still cuts out after 5-10 seconds What I learned: 1: Pump was pretty clean 2: Diaphragm was in good condition 3: DONT unscrew the outlet at the bottom of the tub, the pipe fell down and had to fish it out for half an hour 4: blowing out the hull hose from the pump offers no real resistance 5: not sure about the bath - pump hose, as i couldnt find any way to check for blockages without a long wire maybe? 6: Maybe the engine is seised... Though it runs happily for a few seconds and does appear to drain water from the tub I guess my next step is to either: 1: buy a whale gulper and hope for the best 2: find out if the bath - pump line is clogged (not sure how yet)

Wicked, that's the plan then.

I'll try taking it out, any advice to stop the bath water flooding me? havent managed to drain the bath yet haha

I think - according to my phone as i took a haphazard picture around the back of the bath its this one. https://www.jabscoshop.com/marine/pumps/sink-shower-drain-pumps/50880-1000-self-priming-diaphragm-pump-12-volt-dc.htm

Just tried the plunger, did sweet FA haha

Righto, i'll check out a whale gulper! In the short term, is it possible to try a plunger or would that damage the pump even more? In other news, my pump appears to be a jabsco shower drainage pump

It could be fighting a blockage, however i left it for 24 hours and just pressed the button tonight, it lasted about a second. could it overheat that quickly?