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Replacing Starry Night's 20 year old D4L Eberspacher with a new D4 Airtronic
We took the failed heater to the local Eberspacher agent in Norwich (Panks Auto) for a health check. Testing revealed a defective flame sensor and a short in the control unit which then annoyingly disappeared. Spare parts are no longer available for the D4L unless you want to buy someone else's cast-offs with the associated risks. And even these are not cheap. So we decided to look at getting a new heater.
After a lot of phoning around and research on the internet I had a pretty good idea of what a good price looked like from a reputable agent with an after sales service. Some haggling with Panks resulted in a good deal. They would supply and fit the heater and connect it to the old exhaust on a temporary basis. I would wire in the control unit and connect in the new exhaust, the latter requiring a cupboard back to be removed, access created, and the installation of a new skin fitting.
The old exhaust was an unlagged flexible 30mm i/d stainless steel flexible steel pipe. The new exhaust system is a much sturdier but smaller stainless steel flexible pipe with a nominal i/d of 25mm and comes with an insulation sleeve and an outer flexible duct jacket - much better.
Alan from Panks had the heater installed and up-and-running by mid afternoon. He had to make an adapter bracket to enable the new heater to sit on the old heater's bracket (which was welded to a bulkhead) and line up with the ductwork.
The new heater is a good deal more compact than the old one and fitted in without any difficulty. A new pump and new fuel line were installed too. The beefy pos and neg power cables that I had put in last year were retained and connected to the fuse box with its 20A and 5A fuses that come in the kit.
The heater was connected to the old exhaust via a reducer elbow as the new exhaust is a smaller diameter than the old one.
Mike removed all the old wiring, controls and thermostat and threaded the new control loom through the engine compartment and up into the control console. The new control head fitted exactly into the hole left by the old controller - not by design I must hasten to add!
A few days later I had plucked up the courage to tackle the fitting of the new exhaust. The rear of the cupboard behind which the existing exhaust skin fitting lurked was carefully removed. This was much easier than anticipated as someone had already had to do this to install the old system. Then the old exhaust pipe and lagging was removed leaving clear access for work to commence.
The old skin fitting was hard up under the side deck meaning no swan neck and the danger of water ingress, so a new hole would be required for the new fitting, slightly lower on the side of the hull to permit the exhaust to loop up before heading down to the heater.
The instructions required a hole to be cut in the side of the hull at a 45 degree angle, and for this purpose an extra long mandrel was provided in the exhaust kit to enable the circular hole cutter to be angled. This would result in an elliptical hole and a nice snug fit for the skin fitting. The 45 degree angle is because the pipe on the back of the skin fitting is angled at 45 degrees to start the swan neck. On a boat wit a hull of some thickness - ie a wooden boat - having the hole at the required angle would be essential.
Our hull is 5mm thick mild steel and I did not relish the idea of cutting a hole through this at an angle. So I made a mock up of the hull wit a 54mm circular hole and determined that the skin fitting would site comfortably within the hole with plenty of edge material for the four fixing holes. So I didn't bother with the 45 degrees at all.
After having marked up the hole inside and out and rechecked the dimension n times, I drilled the pilot hole for the circular cutter and then double checked the position of everything all over again.
The actual cutting of the 54mm hole was quite quick and fairly uneventful with the application of plenty of cutting fluid - apart from when the pilot drill became loose, dropped out of the cutter mandrel and fell through it's own hole into the water never to be seen again! Luckily I had a spare drill to fit the mandrel otherwise I would have had to delve for it with my big magnet.
The edges of the hole were ground smooth and primed and the fixing holes marked on the outside from the dinghy. Pilot holes were drilled from the outside for each hole - easier said than done from a dinghy when you take into account that action and reaction are equal and opposite. The harder you push on the drill the further away the dinghy floats!
The final hole for the thread size was drilled from the inside, then it was back into the dinghy to tap the holes for the fixing screws, trying hard not to drop anything more into the marina!
Finally with some sealant applied to the skin fitting it was all installed and connected up.
Unfortunately the supplied 2m exhaust pipe is too short to make a really good swan neck at the skin fitting so I had a stainless steel tube made to extend the length of the exhaust pipe. This was a piece of standard 25mm o/d tube with the ends turned down to 24mm o/d to suite the exhaust pipe i/d. The 25mm i/d Eberspacher exhaust just won't fit over a 25mm o/d tube It's even tight on 24mm! I located the extender tube just after the heater outlet on a straight run in the engine compartment.
The extension tube is lagged and sheathed in the same way as the rest of the exhaust and it is all held in place with the clips provided in the kit.
We are very pleased with the new heater. It is so much quieter than the old one and almost silent when modulated down. However, when it is very cold outside it seems to struggle to meet the target temperature because it modulates down too soon, so you have to dial in a slightly higher target temperature. I expect there is a fix for that, but haven't done the research yet.
The control system is nice and simple to use. Even the tick-tick of the fuel pump seems quieter as the resilient mounting is much improved.
I shall see if I can sell the old heater on e-bay, for spares - you never know, I may get a few quid for it!
The old D4L crammed into a space not really big enough - a typical installation then!
The old heater control switches and timer, looking quite dated.
The new D4 Airtronic
The supplied L-shaped bracket fitted to the grey adapter bracket sitting on the pair of stainless steel brackets that carried the original heater. The black duct on the left is combustion air intake. The one on the right is the outer jacket of the exhaust pipe.
The exhaust connection before the extension was added to improve the swan neck. The insulation is clipped to the stainless exhaust pipe. The old skin fitting taped over at the top waiting for a proper bung to be fitted on the outside. Pencil marks show various positions for the new skin fitting, mooted before the final one.
The view from the outside. The new fitting would have been higher had it not been desirable to put some white paint between it and the red line.
Close up of the skin fitting. You can see the effect of the pipe being at 45 degrees
The controller/thermostat/thermometer. Not normally set to 22deg - just for test purposes!
Copyright © 2009 Mike Hawkridge