Diesel heater not producing much heat

[Babylon]

Heater is a 5yr old Planar unit, which has had occasional light use only. Everything works as normal (warm up cycle, main operation, run-down ventilation, etc) except that it doesn't produce much heat. I don't know if the heat output is per spec as I've got nothing to compare it to, but if it was water then I'd describe it as 'luke-warm' at best.

The heater is located under the cockpit coaming in a near-impossible place to access. Although close to an open cockpit side-locker vent, the air intake isn't directly connected (else risk of drowning and/or death by corrosion if green water comes onboard as happened to its expensive predecessor). So it draws in air from the general cockpit-locker/engine-bay area, which isn't ideal but it's certainly an incentive to keep the engine bay as clean of hydrocarbon smells as possible! The diesel feed is from the main tank rather than a separate reservoir, and my fuel is kept very clean.

It is a small boat so there are only two duct outlets in the cabin. The controller, also located inside the cabin, has an integral temperature-sensor, but even over-riding the sensor and setting it to maximum heat doesn't make any difference.

What could be the reason for poor heat output? Are these things supposed to be serviced at periodic intervals - and what would be the service items?

 

[lustyd]

occasional light use only.

They don't like light use. You need to run it hard to keep it clean internally. Hopefully you just need to open it up and clean out the build up.

Also, are the ducts insulated? I used some wool insulation from Wickes and it helped a lot.

 

[Babylon]

I suspect that might be at the heart of things, but that's problematic as I'm normally only aboard in the warmer months and have little regular need for it. I have run it from time to time just for the sake of keeping it clean, but clearly not enough!

A couple of weekends ago I left it running overnight, which made some difference but not a huge amount. I can of course repeat the exercise, maybe this will progressively improve things...?

 

[Minerva]

Can you leave it running on high for a good few hours to try and burn off some crud?

 

[sealegsjim]

Have you checked the obvious, that the ducting is firmly attached to the heater - mine sometimes work loose

 

[ghostlymoron2]

Sounds like it needs a thorough service. If it's so sooted up I doubt that a long hot burn will sort it but worth a try. Maybe run it on paraffin for a while.

 

[Momac]

Does the hot air output duct near the heater get hot ?
(Assuming its a hot air heater and not a hot water type heater).

 

[fredrussell]

If you haven’t already, get in touch with Owen Cox - he’s the Planar man. He’s on here occasionally.

 

[B27]

Is it producing smoke?
If not, it must be burning what fuel gets into it realatively well.
So maybe the fuel supply is choked?

I had similar with a Chinaspacher, as far as I could tell the trouble was air in the fuel pump, it got better after running for an hour.

 

[Porthandbuoy]

My Planar output got progressively cooler over the course of a year. I stripped it down and found the heat exchanger well sooted up on the inside. Scraped it clean, put it all back together with new gaskets and, importantly, a sintered diffuser where the fuel enters.
One thing you can't get at is the sealed combustion chamber. All I did there was tap it with a small hammer to dislodge carbon and shake it out. When the weather gets a bit colder I intend to run a few litres of paraffin through it which apparently burns hotter and will clear any remaining unburnt carbon.
I think the best advice is to run them flat-out and if it gets too warm open a hatch.

 

[Rhylsailer99]

Fill it with paraffin and run it on full wack for a few hours.

 

[vyv_cox]

Contact Owen. He will respond almost immediately. His philosophy with Autoterm (Planar) has always been to provide top level support.

Do not run on paraffin, you may burn it out. Might work with other makes but they are not allowed the same.

 

[PetiteFleur]

As mentioned earlier, check to see if the ducting has become detached from the heater - first time it happened I fitted a better SS hose clip but it came loose again. Becauseof the heater location there is a right angle plastic bend connecting the heater to the hose. So I fitted a tiny ss screw to fix the bend connector to the heater, then the hose clip. Seems to work when tested.

 

[wingcommander]

As mentioned earlier, check to see if the ducting has become detached from the heater - first time it happened I fitted a better SS hose clip but it came loose again. Becauseof the heater location there is a right angle plastic bend connecting the heater to the hose. So I fitted a tiny ss screw to fix the bend connector to the heater, then the hose clip. Seems to work when tested.

Agree, those flex couplings can have a mind of their own . Mind you looking at my now 24 months temporarily install ( to be made permanent once ime happy with it all) . You can clearly see why i do check on a regular basis lol

 

[pandos]

Is there any way/ chart to calculate the temperature the air should be after so many meters of un-insulated duct at a set ambient temperature?

I cannot get to the heater, if it stops I'll need an elf or a small child, to go into the locker and beat it...

 

[wingcommander]

My 2KW CHINASPACER. One outlet circa 6mtr of run is too hot to keep your hand over outlet after ar9und 10 min of operation . If that helps

 

[pcatterall]

I have sold, serviced and repaired 100s of these heaters over the years as my retirement hobby.
I cant recall many that worked only at the poor output you suggest. My quick output check has been to hold my hand a few inches away from the main output vent.
I would expect to have to 'withdraw' within a few seconds!!

PS I am now retired even from Eberspachers!

 

[wingcommander]

Does the pump speed (Click) modulate down immediately or is it and fan running full clack . Their is a noticeable audible difference.

Sorry just re read opening thread

 

[Babylon]

Thanks for the variety of helpful suggestions! Now back aboard and have had a chance to examine the system more closely. There are two obvious parts to the problem: the heater and the ducting.

With repeated recent running for as long and hot as possible over the last two weekends and again this afternoon, the heater is now producing more heat than before, so this indicates a progressive burning off of crud, which I hope continues!

The ducting hasn't worked loose from the heater, and there is no evidence of smoke in the exhaust fumes out the stern or fuel starvation, but there are indeed several meters of uninsulated ducting in the cockpit-locker / engine-bay space before it enters the cabin space. This ducting feels pretty hot for the first meter or so that is easily accessible, but by the time the air exits the two vents in the cabin it has obviously lost a huge amount of energy! The colder it is (i.e. at night and with the engine-bay no longer warm from a good engine run) the more heat will be sucked from the ducting before it gets to where I need it.

There is a third element that may be involved? After some time running (half an hour to an hour, maybe just fifteen minutes) the controller seems to run the heater cool for a while (i.e. a ventilation cycle, just like when cooling down to stop), or reduces the fan speed... then the heat comes back on...? I have no idea why all this is. Also I hate this controller (and its illogical and incomplete rubbish manual). I just wish Owen had fitted a basic ON/OFF switch with no thermostat - that is all anyone ever really needs out of these heaters on small or medium sized boats: ON for heat, OFF for no heat!

Also, are the ducts insulated? I used some wool insulation from Wickes and it helped a lot.

Have you checked the obvious, that the ducting is firmly attached to the heater - mine sometimes work loose

Does the hot air output duct near the heater get hot ?

Is it producing smoke?
If not, it must be burning what fuel gets into it realatively well.
So maybe the fuel supply is choked?

s there any way/ chart to calculate the temperature the air should be after so many meters of un-insulated duct at a set ambient temperature?

My quick output check has been to hold my hand a few inches away from the main output vent.
I would expect to have to 'withdraw' within a few seconds!!

 

[Momac]

several meters of uninsulated ducting in the cockpit-locker / engine-bay space before it enters the cabin space. T

In my case the heater is under the saloon floor so the ducting which is not insulated makes great under floor heating in the saloon which is of course very welcome. In your case the heat is lost before it reaches the accommodation space. Insulating the ducting should help with your issues.

I have the simple control for my Eberspacher and only use full power by turning the rotary control to its maximum . If it gets too hot in the boat we switch it off or open a window.

Sounds like giving it a good thrashing is helping in your case .