Quick decision on new heating/hot water system

_Mike_

Happy new year! I'm new here, and I was referred by a friend to get some help making a decision in selecting a new heating system. This weekend my Buderus S-150 indirect storage tank failed and I am told needs to be replaced. (There is water coming out the top and running down the side.) My boiler, a Buderus G-124-X, needs a new gas valve due to a fire that damaged the safety switch back in 2008. (this went unnoticed by me, my buddy, and two plumbers)

So we are presently without heat and hot water. We are in New Hampshire, where it is -2 outside right now. We have electric heaters running and wood stove burning to keep the 3000sf home sort of warm, and pipes from freezing.

Background of the home:
- Built in 1980 on a historic stone mill foundation
- 2-story plus poorly-insulated crawlspace (see above - stone foundation)
- All mechanical equipment is in the crawlspace
- Boiler operation typically keeps the pipes from freezing

- Living area marginally insulated
- Single pane windows
- Open concept layout downstairs heated with radiant under the wood floors
- Radiant is glycol filled due to occasional freezing temps in crawlspace below
- single zone, total of 11 circuits
- there is decent insulation between the floor joists that conceals the tubes

- 4 bedrooms upstairs 3 of which have baseboard electric heat
- 2 of the four bedrooms only have 3 walls as they overlook the downstairs with railings
- Heat from downstairs travels upstairs through the overlooks/stairwell

- Full bath upstairs powder room w/ stand-up shower downstairs
- Laundry room
- Kitchen with 1 sink, dishwasher, and icemaker and water dispenser on fridge

- Home purchased in 2004 - mechanical equipment seemed new-ish at the time

- boiler is fueled by propane
- '17 propane use = 1044.4gal
- '16 propane use = 1523.2gal
- indoor thermostat settings typically vary from 55-65 degrees
- thermostat setting varies depending on $ income & presence of guests
- woodstove sometimes used on weekends to supplement propane heat
- Oil is not a feasible fuel source.

At this point, the alternatives appear to be:
1) Fix the gas valve on the boiler, and replace the indirect tank. This would restore the system in-kind
2) Remove the entire system and replace with a single on-demand system for both hot water and the radiant heat. Install a zone in the crawlspace with baseboard heat to keep the pipes from freezing. I believe this would cost around double of alternative 1.
3) Fix the gas valve on the boiler, and use the boiler for the radiant system only. Convert hot water to a low-boy electric so that the propane isn't being used constantly to keep the hot water hot. I think this would cost a little more than alternative 1, but not as much as alternative 2.

A few points my plumber made:
A) We can't do an exclusive on-demand propane hot water heater because the flues would be too close to one another and detect each other's carbon monoxide
The radiant heat should be around 90 degrees, but is much hotter at 140 degrees because it is also being used to heat the domestic water (my wife enjoys scalding hot water - weird, I know...) He says this is a downside of the current system and a reason to, at a minimum, get an electric hot water heater.

So I wanted to see if there is any input on where I go from here. Money is a concern, both in the short term and the long term. Performance of the current system has met our needs with minimal maintenance - no reason to improve performance unless it is a similar or lower cost. And I need to make a decision quickly as we are without heat and hot water. Any thoughts or suggestions?

Again, Happy New Year and thanks!
Mike

EBEBRATT-Ed

fix gas valve replace indirect

Gordy

That's the quickest. That boiler is how old? 1980?

hot_rod

Agree with above suggestions, and check the boiler fluid when they drain it down. It may be wise to run a cleaner to improve performance.

Zman

I agree, fix the boiler. Once you no longer having an emergency, is the indirect totaled or is it a leaky gasket?
I sounds like the indirect should be piped and controlled as a priority load so it can run at higher temps. The boiler should not run at condensing temps, so you would need a mixing valve to get the lower radiant temps.

Gordy

^yes I notice a lot of condensing drip on the flue pipe joints.

_Mike_

This system was probably installed around 2000 or so.

Gordy said:

That's the quickest. That boiler is how old? 1980?

_Mike_

Zman said:

I agree, fix the boiler. Once you no longer having an emergency, is the indirect totaled or is it a leaky gasket?
I sounds like the indirect should be piped and controlled as a priority load so it can run at higher temps. The boiler should not run at condensing temps, so you would need a mixing valve to get the lower radiant temps.

Are you able to tell from the pics if I have a mixing valve? The plumber that came said it's totaled... but I didn't see him looking for a leaky gasket either...

_Mike_

Gordy said:

^yes I notice a lot of condensing drip on the flue pipe joints.

Does the drippage indicate another problem I haven't mentioned? I just thought it was from warm air mixing with cold...

_Mike_

So here's where I am in my thinking... I have a boiler that is approaching 20 years old... and a tank which, if I replace in kind may last 10 years is what some friends are telling me... so within the 20 year lifespan of the tankless system, I will have replaced two indirect tanks and the boiler.

I'm thinking even though the tankless is 2x the cost of replacement in-kind, over the next 20 years it will be less money, have less maintenance, and run more efficiently.

Plumber says he'll work new year's day to install the tankless, but I'll have to wait til Tuesday for him to order the new low boy and gas valve from his distributor.

Thoughts?

Jamie Hall

_Mike_ said:

Gordy said:

^yes I notice a lot of condensing drip on the flue pipe joints.

Does the drippage indicate another problem I haven't mentioned? I just thought it was from warm air mixing with cold...

It may. It may indicate that the return from the radiant system is getting directly to the boiler and that the boiler is running at too low a temperature. This will do neither the boiler nor the flue any good at all. That boiler is one of the better ones out there -- but it wasn't meant for return temperatures below about 140.

Which means your radiant really should be piped primary/secondary.

_Mike_

Jamie Hall said:

_Mike_ said:

Gordy said:

^yes I notice a lot of condensing drip on the flue pipe joints.

it wasn't meant for return temperatures below about 140.

Seems like this would be a reason to go with the tankless system

_Mike_

Seems like return temps below 140 might be a reason to go with the tankless system?

HomerJSmith

Fix it! Did I tell you that I'm cheap?

When replacing the gas valve, remove the burner tubes and clean them, the pilot orifice and anything else down there.

Buy an indirect with a stainless tank and 1" cupro-nickle heat exchanger with a low pressure loss.

Find out why the power vent system is showing all that corrosion.

You know, the indirect doesn't have to be next to the boiler if a further location gives you more head room.

Gordy

That boiler has the silicone cast iron. I believe it can take lower water temps than the standard CI castings. I don't know about radiant rwt. I'm thinking 130 iirc. It also has the logamatic control.