Best Of
Re: Installing new bathroom zone on a pretty screwed up system
That bathroom zone is way too small for such a big boiler even on low fire. The simplest is to tag it onto the main main distribution right by it with a small local pump+thermostat.
If you want to run it back to the main manifold, you can but have to add a buffer or you would have to add some logic so the zone never runs on its own.
Simplest would be a relay driven by the boiler circ in series with the bathroom zone circ power. This way the even if the bath is calling for heat, it would only run the circ if another zone is running.
Also watch those Radiantech pipes are usually not oxygen barrier. You have to watch what you connect up to it as it can't be steel. Not sure if the Weismann will like it either.
I also see mixing valves there. With a modcon, you never want to be mixing. Set the outdoor curve so the zones have good runtimes without any mix. This is basically free fuel savings with no drawback.
Kaos
Re: Installing new bathroom zone on a pretty screwed up system
It sounded like you were adding a new bath. If the issue is with existing not being hot enough, the solution is much simpler.
Add balancing valves to all the loops before the bath zone to restrict the flow. This will reduce how much heat gets to the bedrooms so the thermostat calls are longer and get more heat to the bath. Simple to do and doesn't require any new controls nor does it create micro zoning issues.
Kaos
Re: Should I stick with tankless coil?
That is what I was told when I worked for the oil company. "Where else could you get FREE hot water for 6 months, then from us, your dependable oil dealer!" If you put in a gas or electric water heater, then you will have a higher gas or electric bill for hot water all 12 months.
Free hot water from a crusty tankless coil in a boiler. Really?
That is what my father told me. and he would not lie to his favorite son!
Re: ADVICE/IDEAS NEEDED! 3 Commercial Hot Water Heaters
I always prefer tanks & boiler. The most tried and true I have ever found was the AO Smith HW 300, 420 or 670 boiler & 2 - 119 gals tanks If 2 100s have done ok for you in past. I get 20 to 30 years at least usually out of this set up. Problem is its standard 80% combustion efficiency so you give up some energy savings for reliability. You also may not be able to go std efficiency depending on your states energy codes. I have found nothing that compares for cost of ownership to the above setup. Larry I'm sure is right about checking water chemistry, changing anodes and flushing regularly to increase tank style gas water heaters life.
My .02 worth.
Re: ADVICE/IDEAS NEEDED! 3 Commercial Hot Water Heaters
Test the water chemistry, that will tell you what tanks will last the longest. Steel might be right for some chemistries, stainless for others.
mattmia2
Re: ADVICE/IDEAS NEEDED! 3 Commercial Hot Water Heaters
Hi, Before doing any boiler room work, I'd be measuring shower flow rates and water pressures over at least a 24 hour period. If pressures fluctuate, I'd be looking at pressure compensating showerheads. Neoperl makes the innards for showerheads. I'd be installing 1.5 gpm heads if what you have now is larger. Once that work is done, I'd be metering hot water usage so yo know just what the demand really is. With that info, you can work in the boiler room and size the equipment to the measured need. You might find a lot of savings in equipment costs once the hot water demand is controlled. I know I'm not answering your questions directly, but this sequence of doing the work gives you the best chance of success.
Yours, Larry
Re: ADVICE/IDEAS NEEDED! 3 Commercial Hot Water Heaters
Hi, I'll stay at 30,000 feet for a bit with tank longevity… Things that kill tanks are pressure fluctuations, high pressure (I like to keep it around 40-60 psi), too much water thru-put, making the heater fire excessively, and overly conductive water (reducing the anode's useful life). You can add improper connections, like copper fitting to steel tank, but it's a smaller effect.
A reason I suggested low flow fixtures is to cut the time the heater/s are firing. A water quality report would be useful as well to get an idea of the conductivity of the water and to see if there are things in the water which could be damaging to tanks or plumbing, like manganese. Salt softening is another question. Softening done wrong can dramatically shorten useful anode life.
The elephant in this room is anodes. Have you replaced them regularly? I've gotten 40 years from commercial heaters by doing so. If you have not been doing that, any other measure is close to meaningless for tank longevity.
Yours, Larry
Re: Installing new bathroom zone on a pretty screwed up system
I think Viessmann states boiler must not be connected to non barrier tube in their installation manual. Hopefully it is barrier tube. Although there could be O2 ingress at those fittings.
For under 160 sq ft, you might consider electric mat in the bath?
hot_rod
Re: Snow Melt Mavens, I need your advice
This was something that came up when the Dead Men began converting gravity systems to pumped systems. By bypassing most of the cool water returning from the system the boiler was able to come up to high temperature (and not condense), and that speeded up the heating out there in the system.
