Out with the Old, In with the New... (NRT, Tom F., etc.)

Constantin

Since this house is in rural Maine, there are a couple of housekeeping issues we addressed also. First of all, we installed a "pig feeder" as per Mark Eathertons suggestion. IIRC, it's a 5 Gallon tank filled to 60 psi, which then feeds the system at 20 psi. This way, a leak in the system does not lead to a waterlogged house.

Secondly, we also availed ourselves to the services of Rhomar for cleaning and conditioning. The well water supply is very high in iron sulphites... The boiler water sample I sent to George was so rust-filled that George wondered if we had sent him a steam-boiler water sample as a joke.... it was quite conductive, apparently.

Thus, we also sent in a sample of Tom's household water, which Rhomar (once again) thought might be a practical joke (it was too clean, they thought it was a distilled water sample). As Tom commuted down to the house, he would bring a 55 gallon drum each time and started filling a 300 gallon tank on site with clean water. Then the flushing commenced.

Even if Tom may have thought I was a bit nutty for suggesting a flushing and cleaning, the stuff that came out of the system once we had pickled it with the Rhomar cleaner quickly made him a convert... black ooze crept out of the pipes... sort of like the stuff you'd see on the X-files, but thinner.

System cleaned, Tom did a great job of purging all zones. Suddenly, a bathroom that never heated on the third floor is working fine (the original installer placing a supply manifold below the floor was part of the problem, it's too easy to get air bound). Plus, we got to hunt for all the manifolds, the locations of which neither the owner, the installer, etc. could all remember.

Last but not least, my only contribution to the whole system: A large APC UPS that powers the whole heating system. While the UPS only has a couple of minutes of runtime, the on-site generator usually starts after less than a minute. The APC filters the incoming power and feeds the Tekmars, pumps, and Vitodens clean juice. Works like a charm and the APC can be bypassed in case it breaks.

As the Vitodens can be interfaced with the central alarm system directly, the owners know that the Vitodens is in trouble well before the house temperatures take a dip. Since the boiler room is much cooler now and the electrical supply is much cleaner also, I expect the current crop of Tekmar zone controllers to last a very long time.

While we upgraded the zone T-stats from the older rotary knob style to the digitial ones, TN4 and all that was not in the cards. The new 500-series thermostats are simply not intuitive and there weren't enough wires in the walls anyway.

Constantin

Merry Christmas Everyone!

... I have a short window of opportunity to post some pics from a job well done in Maine earlier this year. You might remember some of my posts regarding the system, here is the before and after story.

Attached below is a composite of two pics I took of the BOP as it appeared before the re-fit. It included a Tekmar mixing valve feeding an 011 that fed 7 zone valves (no bypass!), a snowmelt system (never used, complete with HX), the connections for the DHW warming, etc. Considering that the gentleman who put this together had never installed a heating system before, it was pretty impressive.

Trouble is, he was following the instructions given to him by the supply house, and some of the piping suggestions in particular ran counter to what most of us would consider proper.

Constantin

Misapplying controllers is a problem...

... Mike at Tekmar was quite amused by the creative use of the 152 to stage the two boilers, as the 371 that ran the system is only good for one stage. As piped, the "differential" that the two boilers were supposed to "hold" could never materialize.

The installer had taken a lot of care to follow the application brief, but the supply-house piping suggestions (no Pri-Sec, two atmospheric boilers, etc.) made the whole thing a muddle. Either of the two G124X's (125kBTU/hr ea.) could have heated the house by itself... piped as they were, they made the utility room unbearably hot because the primary-loop flow went through both (which also raises the interesting issue of how to stage them when they're piped that way).

Add to that local technicians who set the heating curve to 2+ (on a above-subfloor RFH system), and you have the perfect recipe for snap, crackle, pop. It worked for years this way but the 371 was starting to act erratically and the fuel costs were driving the owner bananas. One goldline was for the dead snow-melt system, the other allowed the Buderus IDWH to be interfaced with the Tekmar control panels.

They asked me for help, and thanks to the Wall, I knew who to turn to. Better yet, I got to meet some of them!

Constantin

NRT to the rescue!

I contacted Dave and Rob at NRT to have a look at the system and to suggest changes. We quickly came to the conclusion that this system was pretty much beyond repair. The old 371 controller was starting to go on the fritz, the BOP would have to repiped, etc. Besides, the propane was costing the HO a fortune.

Dave produced these two beautiful diagrams for the updated hydronic and electrical circuits. While this might have been a "simple" job for Dave and Rob, these diagrams are a complete roadmap to the system for installation and maintenance. The NRT team also made several design decisions that I think bear notice.

The one high-temp circuit is actually run via the DHW-supply. In other words, it "drinks" its BTUs from the DHW indirect, which is perfect for a little toe-kick heater in a utility room that is about 100ft². It saved all sorts of extra hardware (the 369 simply turns on the pump when there is a call for heat) and it works great to prevent that room from freezing up (happend once when it was -15°F + 30MPH wind outside).

Another neat design decision was the use of the Tekmar zone controllers, manifolds, zone valves, and pumps. Each 369 controls 4 zone valves and a manifold pump. A Grundfos 15-58 keeps each zone supply manifold happy, has flanged shut-off valves to make repairs easy, and is standard issue on many trucks. A PAB maintains the right amount of flow into each zone, as maintainability was one major concern here!

"Better" flow controls via variable zone valves could have been a possibility... but the thing is: the owners aren't techies and something proven, reliable, and simple is what the system needed. While some installers here don't like Erie valves, they seem to be working so far. Continuing the maintainability theme, NRT also opted for the larger of the two condensate filter assemblies.

Please be sure to take a look at the diagrams that NRT developed (attached as a PDF below). Besides solving some difficult control and piping problems, I believe that it is diagrams like these that set a contractor apart from the rest. NRT not only developed these but also put us in touch with Tom Brewer who installed most of the system.

... and I and the owners got to marvel at the results.

Weezbo

The dead taco circ motors with impellers..

suggests that in deed the boilers had Plenty of flow at their disposal.

Constantin

.... in with the new...

... one could describe this job as the rainbow coalition...

NRT performed the heat loss, determined that a 8-32 would fit our needs perfectly. Tom Brewer of Brewer's Heating out of Whitfield, Maine installed the new distribution system, and the local fuel supplier installed the Vitodens.

The local Viessmann rep. thought the boiler looked small for the house, but the owners had used Corbond as their insulating agent during the gut job. Little infiltration results. So far, the unit is maintaining the home perfectly.

Tom Brewer did a fantastic job of kicking out the old distribution system and retrofitting the new distribution system to mate up with the supply tubes. Thus, whereas the old zone valves were mounted on the ceiling of the mechanical room, they are now mounted in an accessible location (imagine that).

As per NRT's drawing, we have two pumps for 4 zones each with a bypass in case there is only one or two zones calling. Post-installation, Brad made the great suggestion to bypass pumps into the supply, not the return, but no worries. A LLH keeps the Vitodens separate from the house and the thing just purrs along.

The local fuel supplier had been Viessmann-certified to install the Vitodens, whereas Tom hadn't had a chance to install one yet. Thus, Tom did most of the work, while the local fuel supplier "just" had to core a hole for the exhaust, hang the unit, connect the gas, and fire her up.

This picture was taken before the post-installation cleanup.

John White

1st job

Constantin,
Just a note....
I like the first job best!!!!(lol)
But, there is a pump HANGING. It will die for sure. I have tried to reiterate this point over time. They can installed horizontally or vertically, but NEVER hang them. This goes for any wet rotor. jhw

Constantin

Hi Johnny!

Believe it or not, the system operated like that for years. Given the supply of pulled 007's in that room, I can only conclude that a couple of them had been sacrificed at the altar of bad installations.

Please note: This is a "before and after". The present Vitodens / Grundfos installation replaced the Buderus / Taco installation. So, the older pictures reflect what Tom, Dave, etc. were faced with before they upgraded all the systems.

As you can see, the current crop of pumps does not feature the same "hanging" feature. :-P

Constantin

Yup,

... a 010 running through 1½" pipe + two boilers with big tappings? That flow must have been cruising! :-P

In an ideal world, I would have measured the power consumed before and after the boiler room re-make. But that is not to be.

What I do know is that the owner is happy, the house is warm, and the Buderus boilers were set aside to heat 2 homes with people who can't afford a new boiler but need heat. The Tekmar 369 and the 010 mixing valve met the same fate while the 371 is probably so far gone that the only possibility is sending it to Tekmar for an assessment.