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freedom to plumb

condenseit Member Posts: 20
edited November 2020 in THE MAIN WALL
Bosch Greenstar Gas combi boiler, with their CZM100 comfort zone manager and two CRC200 controllers (and two Taco 007e pumps). I just added the Bosch controls to replace my Taco SR503 relay and Nest thermostats. Zone 1 supplies the main level in this order: living room, spare room, dining room (CRC200 as HC1), kitchen (under-cabinet blower), and hall (stairwell) and zone 2 supplies upstairs: master (CRC200 as HC2), bathroom, office, then guest room. Our house has baseboard hot water heat designed for 180F I believe (so likely the shortest radiators possible).
I am looking for help in deciding the best order of rooms to supply heat because I am relocating the boiler next summer (gasp). Two reasons for relocating it: all of my DHW taps are as far as you can possibly get away from the boiler; and the noise of the boiler is unbearable. Currently it and the condensate ejector pump are in the basement and bolted to a plywood board that is suspended from the floor joists that also happen to support my favorite sitting spot (my couch), which in turn happens to be under the foot of my bed upstairs. I did not realize this was going to be an issue until the modulating fan of the condensing boiler started after we fired this brand new system for the first time. We replaced a steam heat gas boiler.
The whole story is that all the water lines in my 1905 basement need replumbing, this boiler was just cobbled onto existing lines, and many of them are galvanized. Fortunately the risers to the upstairs bath are copper, as are some of the more modern parts down there: to the kitchen, basement sink and washing machine. So for the cost of a few PEX fittings (my friend has the tools), and maybe a few new intake/exhaust PVC elbows and drilling a new hole in the house (although vinyl siding is easy to patch) I can put my boiler right next to ALL my hot water taps, and this position also happens to be under the kitchen where pump/fan/combustion noise does not bother anyone. It can hum along with the fridge, dishwasher, and under-cabinet heater blower. I am also planning to put in a Prier 108 freeze proof hydrant with one of their shower heads outdoors and it will have the shortest pipe runs of all!

Back to the heat because the bothersome noise goes beyond just the boiler operation. In the master where we sleep, the hot water (especially with the original relay requesting unmodulated 180 water) went directly from HC2 pump to the master bedroom radiators, and click click bang click BANG a couple times a night. This wakes us up and then I just lay there and listen to the boiler run directly beneath my feet. The pipes have continued to bang even though they have been bled. I first bought, installed, and programmed a Bosch FW200 (now for sale along with the SR503 and the Google Nests) to modulate the boiler temperature with an outdoor reset. This did help some, and at least my boiler started sometimes running return temps below 130 and actually began condensing. My plumber just turned the unit to max temp when he showed me how to run it (return temps were around 150F on an average cold day).

The new Bosch controller system seems to have helped (I had to lose the FW200 and outdoor reset) but is there a way to get the heat to come on even more “gradually” maybe, especially in the master bedroom.? Pipes are connected on the big upstairs loop as: master, bath, office. The pipes travel along 2 entire walls of the office and that much pipe makes this room the warmest in all of zone 2. The guest room has a second set of risers from the other 3 rooms upstairs and is last in line to get heat. I am asking you here if maybe going to the guest room first, then office, bath, master might slow the “heat up” of the loop and the baseboards in the master will warm up more evenly and be quieter? I don’t really care about the extra heat in the office, and I could put some foam insulation on the pipes to reduce radiation. Also the guest room is rarely used, so it is not terrible if those pipes make a bit more noise. And the boiler will be below the guest room’s closet (above the kitchen). I plan on attaching feet and legs and some sound dampening to the plywood the boiler is hung on instead of suspending the whole caboodle from the rafters/floor joists. The baseboards staying quiet where we sleep is #1. The lessened equipment noise will be a bonus, especially when I nap on my couch (I’m a side sleeper and the noise goes right to my head).

Back to Zone 1 for one more main question: as the hot water goes from the HC1 pump right to the far corner of the living room, then the spare room, then the dining room where the CRC200 for HC1 is, THEN to the kitchen blower venturi and finally the hall, and with the new Bosch controls the kitchen blower often is not coming on until well after the HC1 007e pump starts. Would it be good to go right off the pump for HC1 to the venturi for the kitchen blower, as the water will be at its hottest? The blower thermostat turns on at 130 and turns back off below 120F and I want the blower to come on as early as possible. The CZM100 varies the boiler temperature based on supply temp and CRC200 temperature data, and that supply temp can go pretty low even right out of the header. Next I think going to the living room as it is most desirable for heat, and I can see the CMC200 for HC1 in the dining room from the couch. Then spare room, then dining room, and finally the hall. I hope to heat the hall the least because a lot of it goes right up the stairs. My plan for HC1: kitchen blower, living, spare, dining, hall. Perfect! Yes or no?

Lastly I am considering some “clamp on” FABTEK FCLC-2 fins for the 2 feet of open 1-1/2” return header line I have because #1 I do not have any registers in the basement and #2 it would be nice to get the lowest possible return temps to the boiler so it condenses with the highest efficiency. Worth something? Add a thermo controlled fan as well maybe :) 120F on 110F off.
I cannot break every joint so the bath has to be between the master and the office, and the spare room has to be between the living room and the dining room. Every other room can be swapped and those two groups can be reversed.
It feels good to write all this down. Cathartic even. Happy Thanksgiving and thank you for reading, and maybe for your thoughts if you would consider replying. I hope I have provided enough info to make a judgement. I hope I am not sounding too harsh on the contractor, and I apologize if I am coming across that way. I did pay a fair bit for the equipment and install. Thanks!


  • Steamhead
    Steamhead Member Posts: 14,863

    We replaced a steam heat gas boiler.
    I did pay $10,000 for the equipment and install.

    So, you ripped out a steam system and put in hot water?

    Also, we do NOT discuss pricing on this forum. See:
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • condenseit
    condenseit Member Posts: 20
    I removed the pricing , thanks. Yes we removed a 1995 Smith boiler, the steam radiators. and capped the chimney (it was going to be a problem).
  • Jamie Hall
    Jamie Hall Member Posts: 17,165
    edited November 2020
    This^^^. Pretty much got what you paid for, I'd say.

    However, getting it right now is going to be much money, though it can be done.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • condenseit
    condenseit Member Posts: 20
    edited November 2020
    A small amount of forethought into placing the boiler for DHW and planning heat circuits or how loud it would be in operation? And no thought to if the condensing boiler would ever condense? I am resigned to having it this way for the winter. This will be a summer project 2021. That costs money I suppose ;) but it will be worth it. I am on metered water and I cry every time I wait for hot water...
    EBEBRATT-Ed Member Posts: 10,371
    You could separate your hot water loops use primary secondary piping and a three way valves. Bring the pumps on below 60 degrees and modulate the valves on outdoor reset. The baseboard will warm up and change temperature gradually reducing the noise problem.

    Too bad. Many look at condensing boilers and only see the fact that they are 90%+ efficient. Only with low return temps does your efficiency come up

    But with most baseboard systems unless they are designed for low water temperatures they are not 90+%

    Before you go to all the grief and expence of moving the boiler why nor insulate the floor joists above and around the boiler and try doing some soundproofing. Get the plywood the boiler is mounted on off the floor joists and support it from the floor Your DHW problem can be solved with a recirc pump on the hot water line
  • condenseit
    condenseit Member Posts: 20
    Let's put moving the unit aside.... Does it really matter if the thermostat is in the room where heat goes first? or last? Asking for HC2 mainly, planning: guest, then master (thermostat), bath, office.
    For HC1 I think it will be: kitchen first (most heat from blower), then living, spare, dining (thermostat), hall.
    Thank you,
  • Zman
    Zman Member Posts: 7,009
    Can you draw this out and post it? I am sure this rambling description makes perfect sense to you. I cannot follow the plot.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jamie Hall
    Jamie Hall Member Posts: 17,165
    The problem -- as you have discovered -- of having the pipes in a loop is that no matter where you set the thermostat for the loop the emitters -- your baseboard -- at the beginning of the loop are going to get much hotter water than the emitters towards the end of the loop. This simply can't be helped. It is possible to design a loop so that at least some of the time it will give satisfactory results; what is needed is to figure out what the heat loss of each space is under some design condition and then size the emitter in that space to give that amount of heat at the temperature that specific emitter will be running at, considering all the emitters upstream of it. The result will not be even when the boiler is running longer or shorter on, respectively, colder or warmer days, but it may be better.

    Since apparently at least some of the piping is available in the basement, you will get better results dividing the system into as many loops as possible -- the best would be one supply and return for each emitter, but that may not be possible -- and running all the lines off one supply manifold and one return manifold for each of the thermostat loops. This way, with balancing valves on the supply lines, you can adjust the flow to each emitter or group of them to get somewhat better balancing.

    You can combine this with @EBEBRATT-Ed 's suggestions and begin to get -- depending on how hot your emitters have to run to keep the place warm -- some of the potential efficiency gain of the high efficiency boiler. Unless the emitters were initially designed for the low temperature water, however, you won't gain much.

    At some risk of sounding crabby, with very careful redesign of the plumbing to the various emitters and relating to the boiler, you may be able to get close to the evenness and controllability of the steam you removed. You will not gain much in efficiency, however, and it will always be much noisier. But note: very careful redesign. You will have to go right back to square one and check your heat losses, then your emitter sizing (it's possible you may have to increase or decrease the sizes of some of them), then redesign and probably reroute some of the piping.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England