During the construction of my boiler panel, I commented that the main loop pipe size seemed too small (it's 3/4"). The contractor showed me that my HydroShark III SH3-36 only used 1/2" to 3/8" lines within it, thus taking away any benefit of upsizing the main loop. Now that the system is operational, only one zone at a time (sometimes two) have the ability to have any flow. IOW, if one zone is calling and the pump comes on, everything is fine. If a second zone calls, though, it might be fine but might rob flow from the first zone. If a third zone calls, game over. One or more zones do not get flow and the pump spins to no avail. My thought is that the main loop should have been 1.25" or even 1.5" line and that the basement loop should not have been a tee off of the heat exchanger, but rather as a 3/4" x 1 1/2" x 3/4" tee off of a main 1 1/2" boiler line. What are you guys' thoughts? I am thrilled to be wrong on this - I just want it to work. Thanks!!

A pic might help!

Your plumber lacks the most basic hydronic design and installation skills. Needless to say the engineering of a radiant floor heating system using a Hydroshark, or any low mass boiler, would be beyond his comprehension.

The reduced size of supply and return lines are engineered to provide minimum flow through the appliance. These lines most often feed, by short tube, to a manifold with multiple tubes, which results in lower friction loss.

Most manufacturers of boilers will advise larger distribution piping dependent on the flow and head loss of the system served.

It is obvious that you have enough pumps and air eliminators, all else is conjecture without proper heat loads and design considerations.

I won't even comment on the electrical...

I was just referred to a client yesterday whom had a Peerless condensing boiler installed in her new house here in Prior Lake, MN. It seems it never did work well in spite of the builder sending 4 radiant floor "experts" to correct the problems.

20 years ago we couldn't get a contractor to believe radiant floors would heat a house.

Hydro shark is a stiebel eltron water heater, why they can call it a boiler I do not know. But it is a flash water heater electric style. No H stamp or boiler rating that I am aware of.
There are better electric boiler choices that will offer built in out door reset, low head, H stamp pressure vessel approval at a similar price.
Correct me if I am wrong. As if it needs saying.....!
Still liking the slow moving water,
Dan

"Your plumber lacks the most basic hydronic design and installation skills. Needless to say the engineering of a radiant floor heating system using a Hydroshark, or any low mass boiler, would be beyond his comprehension. "

Are you saying that this is setup is completely wrong and that I just need to start over? Where is it best to go from here?

Posted By Blueridgecompany.com on 24 Jan 2013 11:47 AM
Hydro shark is a stiebel eltron water heater, why they can call it a boiler I do not know. But it is a flash water heater electric style. No H stamp or boiler rating that I am aware of.
There are better electric boiler choices that will offer built in out door reset, low head, H stamp pressure vessel approval at a similar price.
Correct me if I am wrong. As if it needs saying.....!
Still liking the slow moving water,
Dan

Hydrosharks may look like water heaters  but they probably differ in relevant ways (it may just be control algorithms/parameters) under the hood. The manual says " Warning: Not to be used with potable water systems " in multiple places.  True, they are not ASME labeled, true there is other equipment out there that IS labeled for the application, but that doesn't mean you can't built a reasonable system around them.

There are high-head/low flow fossil burners out there too, and using a high-head/low-flow/high delta-T boiler isn't a huge design hurdle to overcome from a hydronic design perspective. But the designer at least has to do SOME math, no matter what the characteristics of the boiler are, eh?  Hacks using only WAGs and vague rules of thumb are as bound to screw up systems based on a Hydroshark as they are bound to fall short on other projects.  There's no rocket science involved- even first-order simple arithmetic models are usually going to be close enough to tweak into reasonable performance.  But the vagueness apparent in this designers concept of how things work clearly compounded the problem.

I guess then by this logic if I say its a boiler, its a boiler.
If I have a donkey is it a horse?
This is a water heater, they have been calling it a boiler for some time, so it must be true.
oh well, dont really care that much
Dan

Certainly one of the many things that I'm unhappy with is the designer/builder's decision to not use the unions I SUPPLIED TO HIM to attach the HydroShark. As a result, now you have to whip out a torch to change the system. That, of course, is the least of my worries.

So...is this design so far off that this guy shouldn't even have taken my money? Can anyone cite for me what, specifically, is wrong with the setup?

Here's a labeled version of the pic and the original question of line size called out in yellow highlight - even if it sounds as if dramatically more than line size is wrong here.

This low mass boiler might avoid the ASME label because it is dedicated for hydronic heating and perhaps operates below the 15 PSI threshold (not potable water pressure). There should be no reason why it couldn’t be made to work…even if it has a questionable life-span.

ICFfam, have you read the installation manual? Was a hydronic design analysis done and do have any additional data to share?

It avoids the need for an ASME label probably because it is under a certain square footage of radiation (cannot remember exactly how much that is at the mo), but if you look at older fin tube boilers and commercial water heaters (laars, for example), they are often the same product except for the safeties.

Start over with a proper heat load, specifications, including near-piping drawing. This is embarrassing to the trade and surely frustrating to you.

You must have working design before the "plumber" shows up. Unfortunately there is no hydronic heating training or testing for licensed plumbers. It is learn-as-go if you care... Hydro-Shark, aka cheap and well...cheap.

I won't even comment on the electrical...

Is there something ....not quite ...optimized...with it? ;-)

Badger, you are apparently as frustrated as me and even starting to sound a little like me…

ICFfam, please take a look at the table of contents of this book to gain some appreciation of what is required for a proper hydronic heating system design/installation:

Modern Hydronic Heating

Without any design data for your system, it will be difficult to offer design/installation recommendations that will be successful. Too many badly done hydronic heating systems that are never made right by the designers/installers has given what is currently one of the best heating systems a bad reputation. My recommendation would be to see what your state contractor options are for forcing the people who did your system to either make it work right or to compensate you for having to start over to get a new system that works right. Regrettably, some states don’t have much in the way of remedy, but maybe your state does. Most states have at least a small claims court, typically for disputes less than $10K. If you end up starting over, check the credentials/references of people you hire.

main loop piping is too small for all those pumps.
I don't see any primary/secondary piping between the boiler and zones.

these above two points mean that you have massive flow restrictions when many pumps are calling and the pumps are trying to pull flow from other zones instead of the boiler, in effect fighting each other.

sharing heat exchanger with zones is questionable. I can't see what's going on in the piping there but I THINK not all zones are going through the HE, so that's good at least.

you can reuse most of these components, but the piping is a rip out and start over.

I feel I am in good company Sailor.

I have been frustrated for about 25 years now. Yesterday we were out on a Bradford White Combi-Cor that was leaking from the tank. This is not unusual for the older models and the good folks at Bradford White are more than good about standing behind there generous warranty, but the radiant floor heating system attached to it was a disgrace.

1. No air vent or eliminator...none.
2. Potable water expansion tank--on the radiant side--water logged and standing upright without support.
3. Single 200 watt pump for three loop 1000 sf walk-out.
4. Said circulator pumping into hot side of the three-way mixing valve.
5. T&P valve installed in stead of 30# PRV.
6. Homemade pump relay.

It seemed the radiant "thing" really hasn't worked since installed 8 years ago. Fortunate (I guess) that the forced air Lennox furnace was ducted and zoned for upper and lower walk-out and twice too big for the space. I conclude this from the fact that the furnace did not cycle in the 7 hours we were there-- outdoor temperature 9°F for the day.

Worst of all, this was installed by a licensed P&H company, inspected and passed in the Minneapolis metro!

Oh yes, builder and mechanical contractor both out of business.

"main loop piping is too small for all those pumps.
I don't see any primary/secondary piping between the boiler and zones.

these above two points mean that you have massive flow restrictions when many pumps are calling and the pumps are trying to pull flow from other zones instead of the boiler, in effect fighting each other.

sharing heat exchanger with zones is questionable. I can't see what's going on in the piping there but I THINK not all zones are going through the HE, so that's good at least.

you can reuse most of these components, but the piping is a rip out and start over."

THANK YOU for indicating the precise issues with this setup.

'"main loop piping is too small for all those pumps."
My contractor is emphatically claiming that the main loop piping is plenty. I am referring him to the sizing guide at www.comfort-calc.net/pipe_sizing.html writeup that shows that my 3/4" main loop piping can only do 40,000BTU's when I have a 130,000BTU boiler. I told him that I would have thought using 1 1/4" pipe would have been a better choice, but he is indicating that because the piping inside the boiler itself is only 3/8" or 1/2" that going bigger than 3/4" is just a waste and that Bernoulli principles don't apply. Comments?

"I don't see any primary/secondary piping between the boiler and zones. "
There is none. This is a flow activated and fully modulating boiler, though, so perhaps not necessary?

"these above two points mean that you have massive flow restrictions when many pumps are calling and the pumps are trying to pull flow from other zones instead of the boiler, in effect fighting each other."
This is precisely what is happening. When only one zone calls, we're good. When multiple zones call (especially more than two), one zone pump just spins to no avail and the supply line never sees heat - the electricity to spin the pump is just wasted and needless wear and tear on the pumps occur.

"sharing heat exchanger with zones is questionable. I can't see what's going on in the piping there but I THINK not all zones are going through the HE, so that's good at least."
All in-use zones traverse the heat exchanger, but not for heat exchanging per se. The purpose of the heat exchanger is to allow the future snow melt system (which is supposed to use glycol) the possibility of working without freezing. Basically, when the snow melt zone eventually calls (after it is hooked up...), the 58 boiler pump kicks on sending flow through the heat exchanger for return through the 1/2" (too small?) line that you see running above it.

Quote from the contractor:
"Except flow curve...multi pump all good as i told you before you no matter what have by design 3/8 " pipe flow max @ 20 psi also those tables dont show proper loss/ btu for extrapalation total net. Btu's output curve plus static loss/friction rate/specific gravity/velocity...can tinker all day my suggestion to the specific setup is to lower volocity as i would in all other installation point in fact stanind in front of80000btu with 1'1/4 piping to ea boiler and total supply circuit 98% 3/4....15 yrs 30 residents just fine....if no cavitation raise velocity or temp to allow for corrections"

BTW, my heat load for the home is 60,000 BTU/hr at a 0 degree design temp, but the snow melt application is of course the BTW hog in the mix.

An update: the contractor came back and added in a 1" line fed from just under the T. This addition has now resulted in all zones having the possibility of flow and the addition of a true boiler loop, but the non-basement zones continue to mix cold water in on the supply side when the basement zone is calling. Thoughts?

Would the attached be a better design? Changes include: 1. One GrundFos 26-99 pump to handle basement's 10 250' loops, Main level's 6 200' loops, Top levels 7 200' loops, letting existing zone valves control flow to each zone as thermostat's call. 2. Check valve in dedicated boiler loop to never starve boiler, but force all flow into zones to come as straight, non-mixed water from the boiler. 3. Placement of 150000 btu heat exchanger into boiler loop so that when one of the glycol loops call (either the snow melt or the garage), they get the full benefit of what the boiler can provide. 4. Migration to 1.25" pipe sizing for boiler loop and all main supply/return piping. 5. Movement of garage zone into glycol system, taking it off of main house system. 6. Removal of cast air scoop, in deference to 1.25" spirovent. Thoughts?