Winter caught up with us just a day after we arrived in Anacortes, so I set off to replace our failed furnace fuel pump immediately.
Installing the new fuel pump was simple, yet the furnace still refused to start. Our furnace is a great little unit, very reliable and used by the military in many applications. I can't really fault it for individual component failures since we have been using it rather intensively for the last 4 years, with over 4,000 hours logged on the unit as of today.
Fault finding isn't very difficult once you realize a furnace like this needs 3 main things to work:
-Fuel, which I could show was now flowing properly after the fuel pump.
-Compressed air to atomize the fuel in the nozzle and form a clean burning flame.
-Ventilation to push the exhaust out the combustion chamber.
Additionally it needs a temporary igniter when starting, a glow plug to ignite the air/fuel mix.
So back to tracking the whole fuel, compressed and ventilated air circuits.
Luckily, whoever installed the unit on Enfin put it in a very accessible location in the lazarette where you can just sit down to work in front of the unit with access to all major components.
So I cleaned the fuel regulator (apparently the fuel pump failure had blocked the regulator). It acts pretty much like a carburetor, but in a simpler way since there is no need to vary the fuel flow. A furnace needs constant, well regulated flow and does not accelerate or slow down.
The regulator works when the compressed air in the nozzle creates a suction on the regulator, which then opens its float to let the right amount of fuel through.
The nozzle and flame detector were next.
Now, testing the unit I'd get a jet of fuel in the chamber, not an atomized spray, and of course no flame. Clearly that meant no air was getting to the fuel nozzle, and when I rigged a temporary air supply to it, a beautiful flame ignited immediately. Checking the air compressor revealed it had failed too.
Thankfully ITR, the company that makes the furnace is still in business and just down the road in Vancouver, WA so I got them to ship me a replacement compressor overnight while I dismantled, cleaned and re-assembled the old one. The old one works now, so I'll have a decent temporary spare should the new one fail down the road. With over 4,000 hours on the original compressor, I am not surprised its electric motor is reaching its end of life. The full inside clean I did probably gave me a few hundred hours extra use if I ever need it.
Since I had everything open, I cleaned up the combustion chamber on the old mechanical concept of "while you're there, you might as well".
With the new compressor in, I had to yet again check the regulator, and after all this work was finally rewarded with a beautiful clean flame with no visible smoke whatsoever.
The furnace is now purring very nicely, and seems to be working very well. Just in time for winter.
One Nordhavn owner says "We learn our boats one system failure at a time", and this is very true. I'm now a Hurricane "specialist" of sorts and feel well equipped to understand and repair any future problem. I have a box full of relevant spare parts too.
The heat was also on to sort out plenty of other things: After all we've been on the move and traveling for the last 6 months, so we had quite a few things to catch up on.
Provisioning, minor repairs, routine maintenance, vet visit and routine medicals kept us very busy for our whole stay in Anacortes. Di and I joke that marina days are our busiest days, and that we need a vacation to recover from all the action.
A huge thanks to our friends at the Nordhavn Anacortes Office, who are always around to help.
A gale warning is in effect and we'll be off to hide in well protected Prevost Harbor in Stuart Island tomorrow.