Summary of Meeting With Medco 1-15-2016 Regarding Boiler Status

Bruno-Medco
Patricki
Claude

Medco is really not the right company for the job.  They mostly do new installations.  They use an outside contractor for service.

Mercury Mechanical was the recommendation from Bruno but he also gave Merrion Mechanical.  Patrick has the correct spelling.

Bruno was quite informative on the systems in general but was not that familiar specifically with Laars boilers.

He looked at the venting-
   Using a bend at the end of exhaust is usually ok.
   The pipe run length is probably within limits based on quick measurement and counting of bends.
   There is a screen on one of the intakes that should be removed and replaced with larger "bird screen".
   He didn't think much of the idea that the pipes were somehow clogged with sediment.

He looked at the temperature gauge on the return and dismissed the reading because the return temperature sensor on the tekmar was showing significant heat loss through the building (I turned off the manual pump). 

The tekmar takes readings on 1) the return water temperature 2) the supply temperature and 3) the outside temperature 4) the room temperature desired. It calculates whether to call for heat and if so whether to call for 1, 2 or 3 boilers based on the readings. It's similar to the heat timer that we had but more high tech.   It also keeps readings on the number of hours that each burner has run (historical).   It is supposed to rotate the boilers with one as primary, one as secondary and one as tertiary. After a certain number of hours (like 100 hours or something) of running, it rotates the sequence and so on.  No 1 boiler was nearly twice the other two.   He checked the dip switches and found that the rotate dip switch was NOT set to rotate so he moved it over.   The tekmar has a setting for room temperature which was at 70 degrees.  This is not like a thermostat in a room.  It is only a reference point. It does not guarantee 70 degrees in the room, it is only a number used to calculate the demand for heat.  He bumped it up to 75 degrees. That may improve heat in the units and we can go higher if need be. 

Once the tekmar calls for heat on 1, 2 or 3 boilers, they start up and heat the water flowing through to the set point ON THE BOILER.   As long as the tekmar is calling for heat, the boiler(s) will run up to that set point and continue to heat the water until the tekmar no longer calls for heat.   He noted that the #1 boiler (the one with the high temp stack sensor error all the time) was running up pretty high.  It was running up to 183 degrees. He suggested that we might lower that temperature to 175 to keep the stack cooler.  The boilers also have a modulator which controls the gas flame and the blower and therefore the temperature of the water.  He suggested that faulty modulation might also be causing it to run up to 183 so that the aquastat in the boiler was not turning the boiler off as it should but that the  stack sensor was doing that.  He was not familiar with how to change that setting in the Laarz units.  The manuals I have do not describe it.  I have a feeling there must be a "programming manual" which I will try to locate.

At the bottom of the stack in the boilers there is a drain which flows through a neutralizer cannister (for the emmissions mixed in the water) and then out into the floor drain.  He said in passing that they should be cleaned and serviced. Not a big job.

He also noted that #1 and #2 started a little rough and that should be addressed.

I turned off #1 since it seems to be running hot and tripping the stack sensor. When #2 took over the job, I noted that it  went to 175 degrees and held steady for the duration.

The work that is recommended first:

1. remove intake fine mesh vent screen in rear of building and replace with "bird screen"
2. service neutralizer cannisters
3. address the rough start up of 1 and 2
4. lower the setpoint on 1 (through programming) and/or check the modulation
5. Play with the room temperature on the tekmar until we get enough heat
6. Put the covers back on to ensure that air intake comes from outside not inside
7. replace control buttons on #2

I'm familiar with the theory of the old heat timers and the tekmar is essentially the same. They are at their worst on days which are in the 50's because not enough heat is called for so there is not enough penetration of heat into the building.