Recommendations on wall hung lp water heater for radiant.

Ericjeeper

Built a new shop 30x40 x16' high.one 36"walkthrough, one 16x14 insluated overhead door. Two inches of closed cell goam walls,and roof. Two inches of styrofoam underslab.1260 feet of barrier pex going in the concrete 12" layout.
Now I am looking at a wallhung water heater. Seems most of the smaller btu ones are plumbed 1/2 inch in and out. I am thinking maybe going with the takagi jr.
Not sure what pump I will be using as of yet,but most likely a three speed of some sort.
Thanks in advance. Eric in central Indiana

Rich_49

If you must go wall hung forget the water heater and use a boiler . plenty of price point mod cons out there more adept at doing your job . Water heaters are water heaters , not boilers . If you were asking about a tanked unit it would be a different story .

Ericjeeper

What will a boiler do for me, that a less expensive water heater won't?

kcopp

Flow.
High head losses to over come.
Tankless WH are not designed to run constant.
Not designed to have hot water returning back through them at higher temps.
In fact most all tankless WH Mfg. severely reduce their warranties if you use a recirc pump w/ them.
Boilers don't have these issues because they are designed for space heating.
Tankless WH are just designed to heat up domestic HW.

Ericjeeper

Ok, I appreciate the explanation. Now to find one that won't break the bank.

kcopp

My suggestion....
http://ibcboiler.com/ibc-products/hc-series/

HVACNUT

> @Ericjeeper said:
> Ok, I appreciate the explanation. Now to find one that won't break the bank.

It seems like you've done a fine job in the construction of the garage. Give the same amount of love to the heating system.

Ericjeeper

Yeah I get you, I will have spent almost half again what the building cost, Just in insulation.
Radiant is not a big thing around here. I installed it in my new house in 2004 using a Bock fuel oil fired water heater.Then I added an array of used solar panels into the system.(Picked them up iin the hills of Missouri,at HotRods). Then built an outdoor wood boiler.
So I enjoy doing things myself,even though some would say I also do it the hard way too.

FranklinD

You’re not alone...I built a new small garage/shop this summer (24x28x12) and between insulation and the heating system, I will have spent almost 40% the cost of the structure itself. R55 in the ceiling and R15 in the walls, 2” foam under and around the slab.

But in the end, when it’s -20°f outside, I’ll be warm and toasty out there, so it’ll be worth it. Next year some snow melt tubing will go into the new walkways I plan to have poured. Once you start, it’s hard to stop!

Ironman

@Ericjeeper
Have you done a load calc?

Probably the smallest mod/con would do the job, but that's where you need the load calc to confirm. It will also help to determine how the outdoor reset curve needs to be setup on the boiler to save $$ and keep the slab from over-heating. Another reason that you need a boiler to do the job.

Another mod/con with a good price point is the HTP UFT. It has a fire tube heat exchanger and a 10 to 1 turndown.

Ericjeeper

No I have not done any sort of load count.

Ironman

SlantFin has a free app that you can download that works well.

Ericjeeper

Available to me , a homeowner. Hydrosmart HS120 Con for$xxxx. Energy factor at .93 lp
Btu output 13,950-111,600

Paul Pollets

Viessmann Vitodens 100 is affordable and easy to set up.

Ericjeeper

I have one zone,why would I need a primary/secondary pump set up?
Hydroshart says without,it will void the warranty. I figure my installating it myself will void their warranty too.

Ironman

Ericjeeper said:

I have one zone,why would I need a primary/secondary pump set up?

Hydroshart says without,it will void the warranty. I figure my installating it myself will void their warranty too.

The number of zones is not the issue; the heat exchanger requires that a certain flow rate be maintained through at all times. I'm not familiar with that brand, but if it has a high head HX, then usually the zone circulator is not sufficient to maintain the needed flow.

Ironman

I just looked at the Hydrosmart brochure and I/O manual. It appears to be nothing more than an instantaneous water heater that they're pawning of as a boiler: copper HX, flow switch activated, no ODR, 99* minimum SWT, high head loss HX, etc.

Don't be fooled by the cheap price: it's not a true boiler.

The 99* minimum SWT is NOT what you want. That's probably the MAXIMUM SWT that you'd want on the coldest day of the year. You need a boiler with ODR that will vary the SWT based upon the outdoor temp so that the slab won't over-heat the building.

A slab is nothing more than a huge rock with great mass. It takes a lot to get it heated up, and it will give off that heat for hours. It doesn't matter that the stat has stopped the pump and burner; the slab will emitt its heat for hours. If it's been heated too high because the SWT was too high, then it will over-heat the building. It's called the flywheel effect. ODR varies the SWT to match the load so that the slab won't over-heat.

Please don't let the enticement of low price cloud your good judgement.

Ericjeeper

Paul Pollets,there is no viessman dealer in Indiana.
I figure as a homeowner, not professional they are going to try to break it off deep in me.
Can anyone recommend a supplier?
Indiana is the land of scorched air heat.

Ironman

How about this one:
http://www.supplyhouse.com/Rinnai-E60SRN-E60SR-60000-BTU-Condensing-Wall-Mounted-Heat-Only-Boiler-NG

I put one in a few months ago. Not a bad boiler at all.

Do NOT over-size the boiler! Bigger is not better in boiler land. Do the load calc to confirm the size needed. There are no short cuts to doing this right.

Ericjeeper

Ok if I entered in all the correct data, slant fin say 20580 btu to heat to 65.
I would say this is close. It will be tight once the closed cell foam is applied.

bob eck

Lochinvar Noble combi boil great boiler for the price can be used as boiler only.
Lochinvar Knight wall hung boiler. Smallest is 55,000 BTU input. Boiler only.
Burnham Aspin (formally K2FT boiler) 85,000 BTU input
HTP Elite boiler only 55,000 BTU input
All above boilers are condensing gas boilers wall hung with SS fire tube heat exchanger.

All vent with PVC pipe and fittings if local code allows that.

W/M has a boiler model GV90+ smallest is 70,000 BTU input. This is a floor cast iron boiler with a SS heat recovery and it vents with PVC pipe and fittings if local code allows that.

Navien, Rinnai, Bosch, Buderus, W/M all have high efficiency condensing gas boilers.

There are 85% AFUE cast iron boilers that can be side wall vented with SS vent pipe.

Use a boiler not a tankless gas water heater.

Boilers are designed for heating systems. Tankless gas water heaters are designed to heat water for showers ect...

Find a good local contractor and a good wholesaler who has parts in stock. Boiler will break down some time and of course that will be when it is cold outside.

Ericjeeper

I am afraid these boilers are just out of my pricerange.
I might have to just set a 40 gallon water heater in the corner and do it that way
I thank you all for your input and time spent.

Ericjeeper

Ok, I am now considering a Triangle Tube challenger solo cc50s.
Any cons to this unit?

kcopp

Great choice... Sister boiler to the IBC HC

Zman

Ericjeeper said:

I am afraid these boilers are just out of my pricerange.

I might have to just set a 40 gallon water heater in the corner and do it that way

I thank you all for your input and time spent.

kcopp said:

Great choice... Sister boiler to the IBC HC

This is a classic pay now or pay later.
The triangle tube is a nice unit.

Ericjeeper

Ok, installed the triangle tube 50.works like a charm, zero issues, easy install.
Next project, my house built in 2004,radiant in slab. Opted for bock oil fired water heater. Bock has been mainly used for domestic hot water for the past 12 years as I built an owb and have been heating with firewood.
Now with next chapter in life, we wish to winter in Florida.
Due to the cost of heating oil as opposed to lpg. I am looking for a combi wall hung. I was pretty much set on another triangle tube. Called the dealer, he says he is now carrying the Lichinvar Noble line. But, he can still get me a Challenger.
We have two full baths, he says we need 160k.the heatloss from way back says 72k.
In your expertise, which should I hgo with?

lchmb

put in the proper size boiler and add an indirect. You wont be using water during the heating season so over sizing will just lead to issues down the road..