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Friday, September 12, 2014

Heating system

One significant system on our boat is the diesel heating system.  For a variety of reasons, I'm kinda the general contractor for the heating system.  The good side of that is that I got the heating system I wanted even though there is nobody in Southern California who knows these systems (the expertise is all in Seattle where people actually need heat on their boats).  The down side is that commissioning the system is somewhat my problem.


Heating system in the Laz


The original plan was to hire an expert from Seattle to come down for a week or so to check everything out, test for and fix leaks, test the electrical control side of things, complete the exhaust hookup from the boiler to the hull fitting, fire the boiler and test the system, then go home.  It should come as no surprise that the estimate for this work was about 2x what it would be if I had the work done in Seattle.  We need to fly someone down and back, put them up in a hotel, rent them a car, and pay a lot of overnight freight charges for equipment, tools, parts, etc.  And then there are all the unexpected delays, which are to be expected.  If you have ever done a project like this, you know it's an endless series of little road blocks.  For example, you figure out how you want to route the exhaust, then you need to order the fittings - and wait.  Normally you would go work on something else until the parts arrive, then resume the project.  That works fine if you are local, but not so well if you have flown in for just this project.  I had visions of lots of idle down-time while the clock is running and I'm paying for overnight shipments a couple of times a day.  It started to look like commissioning was going to cost 50% again the cost of the whole heating system, and perhaps more.  Oh, and I'm planning to go to Seattle after taking delivery of the boat.

All this led to a change of plans, and now in hind sight I'm really glad it did.  I realized that most of the system could be tested and fixed "dry", and that almost everything else could be tested (and fixed) without firing the boiler.  If I could do all that myself, I could verify and fix all the installation work that the yard did, get PAEs help fixing any install problems, then finish the boiler install and testing once I get to Seattle.  There would be no flying people around, no idle time waiting for parts, and giant Fed Ex bills.  Sounds much better.

As a brief aside, the other option was to leave the whole project until we got the Seattle and have the work done there.  The risk is that any issue related to the build would be PAEs responsibility, which would require separately tracking time and materials for those parts of the work, billing it back to PAE, getting warranty work approval, etc.  That just sounded complicated to me, and I felt much better with an approach where I was confident that the yard's work was correct before taking delivery of the boat. Some problems are minor, but others could have required significant work, and it's better to flush those out early rather than later.

So, Captain Electric (that's me, according to Laurie) changed uniforms and became Pete the Plumber.  Here was the general game plan:

  1. Pressure test the system with air to find and fix any and all leaks.  It's way easier to fill and drain a plumbing system with air vs water, and leaks are much easier to clean up.
  2. Test all the zone controls, fan controls, and heater ducting to be sure the controls work and control air flow in the right places.
  3. Fill the system with water, and test it with engine heat.  One feature of the system is a heat exchanger that takes waste engine heat and uses it to heat the water in the heating system, just like it heats the domestic hot water.  This lets you have heat while underway without having to run the boiler.  It's truly "free" heat since all that engine heat is otherwise dumped into the ocean.
With these three steps, I could test and verify everything except the actual boiler unit itself, leaving only one isolated part of the system to test and commission, and it is a part that the yard did nothing with other than bolt it to the deck.  And that remaining part is the one that requires some expertise as opposed to everything else that even Pete the Plumber can handle.

Part 1 - Pressure Testing:  All the disconnected hoses were a good starting point.  For some reason the yard had not connected the main supply hose from the boiler and had not installed the pressure relief valve.  It was probably due to missing parts, but I'll never know.  Long story short I got all the parts and got the supply hose connected and the relief valve installed.


Unconnected pipe fittings

The first attempt at pumping it up with air held for about 5 seconds.  A quick run around the boat  revealed that all the bleeder valves were loose.  I also discovered two heater units where the bleeder valves were never installed.  Add that to the problem list.  I tightened up all but one.  There is a nice corner under the galley counter where one of the AC units lives along with one of the heaters.  The trouble is that it's completely inaccessible.  The only way in is to remove the dishwasher.  This took us off on a tangent exploring whether a removable panel should be cut into the cabinet to make the area accessible.  After much back and forth, we concluded that the better plan was to get good at removing the dishwasher.  So out came the dishwasher followed by a couple of plumbing modification to make it easier to get it in and out without having to disconnect anything.

OK, now back to whatever we were working on..oh yes, the heating system.  With the dishwasher out I was able to close off the bleeder valve and continue on.  PAE installed the missing bleeder valves and fitting and after working out a couple of leaks everything looked tight except for a slow overnight leak.  Isolating the different zones narrowed it down to the PH loop which also includes the expansion tank at the high point in the system up in the fly bridge brow.  I chased that one for a long time and finally discovered that the cap in the expansion tank was leaking ever so slightly past the cap and into the overflow bottle.  By replacing the cap with a pressure tester I was finally able to verify that the system was tight.  I can't imagine what mess and pain it would have been to sort all that out with water rather than air.

Part 2 - Zone controls and ducting:  There turned out to be a handful of issues with this, but most were easy to fix.  There is an LED pilot light on the main control switch and it was wired in backwards so didn't light.  There also was an error in my wiring diagram that also messed up the pilot light.  All the ground connections for the fans are switched by a thermostat attached to the heater manifold.  The switch only closes after the water has reached 120F and locks out the fans until then to prevent them from blowing cold air.  I had the pilot light tied to the same switched ground so it would only come on if the water was hot.  Oops.  For testing, I just hot wired the thermostat.  I also discovered that the fan lock-out thermostat  had been mixed up with another thermostat that tells the boiler that the domestic hot water needs to be heated.  One of the switches turns on when the water gets hot, and the other turns on when the water gets cold.  Swapping them really confused the whole system.

Control Panel

With that sorted out and the thermostats hot wired, I was able to test each zone to see if the fans worked, whether they blow air out of the right ducts, and whether all the fan speed controls work.  The good news is that all of them worked correctly.  With help from PAE we got the correct thermostats installed in the right places and everything buttoned up.

The last part of the control system that needed to be tested was the boiler lock out.  When running the heating system off of the main engine heat, the diesel boiler is disabled, but everything else works including the circulation pump.  I set out to test that part and nothing seemed to work right.  The boiler always seemed to be enabled, and the circulation pump wouldn't come on.  After a lot of digging I discovered that Sure Marine (the suppliers of the heating system) had changed the boiler control to a newer version and hadn't let us know about it.  This newer boiler control required completely different lockout and circulator wiring, and required another control box that we didn't have.  Sure Marine got me the missing control box, and after a day of installing the box and rewiring, it finally all worked.

Part 3 - Filling with water and testing with engine heat:  With the controls working and the system leak-free, I filled it up with water.  I used the same water meter that I used when calibrating the holding tanks so I'd later know how much antifreeze to put in to get a 50% mixture.  24 gal later, it was full.  On our sea trial to Catalina after the engine was all warmed up, I turned on the engine heat which started the circulator.  I checked the pipes and manifold and could feel things warming up nicely.  After a little warm up it was show time.  I turned on the heat in the pilot house and voila, heat came out the duct.  Checked a few other zones and sure enough, they work!  I love it.

Now all that's left is to get the boiler exhaust finished and fire it up, but I'll wait for Seattle to get that done by an expert.

4 comments:

FlyWright said...

Holy smokes, Peter! What a lengthy process to get your boat to blow hot air! I bet that first warm breeze put a smile on your face. Very cool!! (pun intended)

Peter Hayden said...

No smoke - thankfully. Yes, it was more of a project than anticipated, and I'm sure glad I didn't hire someone to come down and do it. All told I probably spent 3 or 4 days on it, but it was spread out over several weeks.

Paul Nelson said...

Fascinating stuff - and rewarding for you. But what has your wife been doing during this lengthy commissioning work?

Peter Hayden said...

Good question, Paul. She's been just about as busy as me. There was a week where she was pretty bored, and she went home for a week for a previously arranged family event, but other than that she's been working hard too. Her equivalent to the heating system has been towel bars. I think she bought 3 or 4 different sets before she found one that worked. Then she installed them all, including modifying a couple of them for a better fit. She also managed all the carpet, shades, blinds, and other interior projects. And for the past couple of weeks she's been figuring out where most of our stuff will go on the boat and getting it set up. So she's been real busy too.