Possible heating upgrade is a Combi right for me?

nac

I have shore house in NJ. It is a late 80s build single story 2x4 average  Construction 1,650SF. My central located mechanical room has a boiler and 40 gal hot water heater and a stacked washer dryer. The 40 gal water heater is on it way out. The boiler is I am assuming  original to the house a Burnham P203W. I have about 100LF of baseboard. I was thinking of  replacing both units with a combi and save some space. Also since the house is used mostly on weekends from April to December  it would save some money not having a tanked water heater. The house is heated in the fall and winter if I am not there at 55 min. My local plumber installs Navian  not sure if that is the brand I want to go with. I have researched a Locinvar  Noble  I reached out to their rep only have 3 local contractors in my area only 1 got back to me and his price seems very excessive to what other plumbers have told me. I am in Construction mostly excavation and concrete. Any opinions and suggestions would be appreciated.

Rich_49

Did anyone figure out the heat loss of the house ? This should be done or else you'll just end up with an oversized boiler / combi . Yes , it can be oversized , modulation and water temps cannot address short cycling . Call more contractors and try not picking a boiler brand for your search . Hell ,call us .

Never discount a guy because his price is higher than others' , those others are the biggest reason this site is so busy and wht other guys spend so much time fixing nightmares .

Ironman

Combi’s are rarely a good fit for most homes - in spite of what manufacturers claim. In order to get 4-5 gpm domestic production, you need a 199k btu burner, but the radiators in your house can only emit 50k btus and that’s only needed on the coldest night of the year. At 35-40* outside, you only need half that much. That would make the 199k btu boiler 4 times too large for most of the heating season. Add to that the fact that you’re keeping it 55* inside, and it only exasperates the situation. The boiler will have a shortened life span due to short cycling.

I know fully well that the boiler can modulate its firing rate, but the purpose of that is to match the the firing to the actual heat load, not to compensate for being grossly oversized.

The best solution would be to install a property sized mod/con boiler with an indirect water heater.

I really like the HTP EFTU fire tube boiler and their SS indirect. It’s what I put in my house.

I’d recommend that you contact @EzzyT and see if he covers your area of NJ.

The installer is 98% of the equation and he’s the best.

nac

Rich_49 said:

Did anyone figure out the heat loss of the house ? This should be done or else you'll just end up with an oversized boiler / combi . Yes , it can be oversized , modulation and water temps cannot address short cycling . Call more contractors and try not picking a boiler brand for your search . Hell ,call us . Never discount a guy because his price is higher than others' , those others are the biggest reason this site is so busy and wht other guys spend so much time fixing nightmares .

Do you go to Bayville NJ? No heatloss calculations where done that I am aware of. Also need to install some more base board in the kitchen and Master bath  as there is none.

nac

Ironman said:

Combi’s are rarely a good fit for most homes - in spite of what manufacturers claim. In order to get 4-5 gpm domestic production, you need a 199k btu burner, but the radiators in your house can only emit 50k btus and that’s only needed on the coldest night of the year. At 35-40* outside, you only need half that much. That would make the 199k btu boiler 4 times too large for most of the heating season. Add to that the fact that you’re keeping it 55* inside, and it only exasperates the situation. The boiler will have a shortened life span due to short cycling.

I know fully well that the boiler can modulate its firing rate, but the purpose of that is to match the the firing to the actual heat load, not to compensate for being grossly oversized.

The best solution would be to install a property sized mod/con boiler with an indirect water heater.

I really like the HTP EFTU fire tube boiler and their SS indirect. It’s what I put in my house.

I’d recommend that you contact @EzzyT and see if he covers your area of NJ.

The installer is 98% of the equation and he’s the best.

Thanks for the reply. But wouldn't  a indirect  be not as efficient  especially in the summer when the boiler is not operating? I could be totally wrong that is way I am trying to do my research now and not make a mistake I have to live with.

PC7060

Go with the indirect.  Very efficient and reliable and the impact to heat load in summer is negligible. The boiler would be running one way or the other to meet domestic hit water requirements.

If you are worried about wasted heated due to standby loss from the tanks during the winter, it’s a non-issue provided the boiler and tank are inside the building envelope.  Any loss from the indirect would simply contribute to maintaining the temperature of the home.   

Ironman

nac said:

Ironman said:

Combi’s are rarely a good fit for most homes - in spite of what manufacturers claim. In order to get 4-5 gpm domestic production, you need a 199k btu burner, but the radiators in your house can only emit 50k btus and that’s only needed on the coldest night of the year. At 35-40* outside, you only need half that much. That would make the 199k btu boiler 4 times too large for most of the heating season. Add to that the fact that you’re keeping it 55* inside, and it only exasperates the situation. The boiler will have a shortened life span due to short cycling.

I know fully well that the boiler can modulate its firing rate, but the purpose of that is to match the the firing to the actual heat load, not to compensate for being grossly oversized.

The best solution would be to install a property sized mod/con boiler with an indirect water heater.

I really like the HTP EFTU fire tube boiler and their SS indirect. It’s what I put in my house.

I’d recommend that you contact @EzzyT and see if he covers your area of NJ.

The installer is 98% of the equation and he’s the best.

Thanks for the reply. But wouldn't  a indirect  be not as efficient  especially in the summer when the boiler is not operating? I could be totally wrong that is way I am trying to do my research now and not make a mistake I have to live with.

No, the indirect would be more efficient than your present gas water heater and would have the full firing rate of the boiler directed to it when needed. That would mean it would recover in half the time of your present water heater.

Call @Rich_49 or @EzzyT. They’re two of the best.

JUGHNE

Being a weekend only house, during the non heating season, you could switch off the boiler for the 5 days you are not there.
When you return and switch the unit on it will take little time to recover, actually the tank will probably still be warm.

You don't do this now with your WH, it can run all week.
I would guess that an indirect is much better insulated than your existing water heater tank. Your old WH has a 3" pipe up the center of the tank, designed to pull air up and out thru the chimney.....24/7/365.....cooling the tank the whole time.

hot_rod

Does the home heat comfortably now with the 100 feet of baseboard?  If so you could be looking at a 60- 80,000 mod con 

The heat load will confirm the sizing

Next question us how much DHW you need or want. Does the 40 gallon provide adequate hot water? 

A 110- 120,000 combi would give you 2.5- 3 gpm of continuous hot water, no waiting for a tank to recover. The combi would free up some floor space.

That size combi would turn down to about the same low firing as a mod con that was not a combi

If that 1650 sq ft comes in with a load in the 40 50,000 range you nay be able to run lower temperatures in that amount of fin tube.

Rich_49

Yes we go to Bayville . I am in Toms River .

nac

hot_rod said:

Does the home heat comfortably now with the 100 feet of baseboard?  If so you could be looking at a 60- 80,000 mod con 

The heat load will confirm the sizing

Next question us how much DHW you need or want. Does the 40 gallon provide adequate hot water? 

A 110- 120,000 combi would give you 2.5- 3 gpm of continuous hot water, no waiting for a tank to recover. The combi would free up some floor space.

That size combi would turn down to about the same low firing as a mod con that was not a combi

If that 1650 sq ft comes in with a load in the 40 50,000 range you nay be able to run lower temperatures in that amount of fin tube.

The kitchen needs some baseboard as there nit any in there now. The master bath also need baseboard  as there is in wall electric unit right now that is not used. It heat up ok I would say when I turn on the wifi thermostat from 55 to 70 when I do go it will take 4-6 hrs to get up to temp.  I don't know if that is normal or not. The house has 2 bathrooms  1 is shower only the other has a jacuzzi tub. It is normally only 3 people in the house. The space issue  really is not a deal breaker as I have enough room for my stacked washer dryer right now.

nac

Rich_49 said:

Yes we go to Bayville . I am in Toms River .

Ok will definitely give you a call have to try to get down there to clear all the snow we got.