Need help with heating & hot water setup for tight space

[alwayslookaround]

Hi. I'm new to the forums here. I am in need of some help/input, any feedback is MUCH appreciated.

My situation:

- 1200 square foot condo apartment in Brooklyn, NY. On 2nd floor of a 4 floor building. Major heat loss is 2 exterior walls, all other walls touch 'warm' living spaces.
- Boiler closet within apartment is 36" wide, 31" deep, 7' high.
- Gas connection
- Current setup is a wall mounted atmospheric boiler. 100,000 BTU. Made by Myson, Apollo model. Completely dead now. Domestic hot water is from an indirect tank, 36 gallons. Made by Crown. Only 2 years old, still works fine. I'd like to keep/reuse the indirect tank if possible, will replace if I have to.
- Nobody makes a wall mounted atmospheric boiler these days. They don't exist. All wall mounted boilers have to be direct vented. I can't install a direct vent. So I have to use a normal cast iron floor boiler.
- I can't find a boiler + indirect tank combo that will fit within the tight space constraints I have. I've been looking at a bunch of 80-100,000 BTU boilers, none are small enough to fit along with an indirect tank.
- I can't support an indirect with the walls, the walls are not strong enough.
- If I can't fit an indirect tank along with a new boiler on the floor, I'm considering an external tankless coil. There's one made by TFI EverHot: http://www.tfi-everhot.com/ExternalTankless_2008.html. I'm looking at the 4 GPM or 6 GPM, which are small enough to fit in my space with a floor boiler. Does anyone know this company? Are they reputable? Will they really hold up to that amount of domestic hot water output? If so, for how long?
- I realize the external tankless coil solution is not the most energy efficient. It will also require an additional circulator pump, and I'll probably want a priority valve for when the heating system is on AND I need hot water at same time. So all in all, I don't love this solution. But I can't find another option. Is this option not so bad in reality, and I should just accept it?

Like I said, any feedback is MUCH appreciated. I've been stuck with no hot water for 1 week already, I really need to find a solution and have it installed.

Thanks.

Mike

[BaldLoonie]

How much room do you have for the boiler itself? Got a picture of the closet?

100K for a small space with little outside exposure is way too much. Probably need 1/2 that even with water heating.

[SolarMike]

Is the atmospheric myson boiler going straight up to the roof and if so what is the flue size? It is quite possible that most of the wall mounted boilers will vent up to the roof IF an approved PVC or CPVC or PP vent pipe will fit down the existing vent, leaving room for the combustion air to come in around it.

Many are 2 or 3" exhaust vents and if you currently have a 5 or 6" flue, you will do fine. I have done this with the Viessmann Vitodens100 boilers many times but you will have to find out if it is allowed in your area. Try to find a good local dealer to determine the feasibility. There is a tankless add on for the Viessmann boiler or you can have it feed the indirect.

[kangaroogod]

You could consider using a combination boiler such as a navian. You may need a beefy gas line. I too would like to know what the status of the chimney is. Is it a shared chimney?

[beenthere]

A 4GPM tankless would need a boiler with a min of 138,000 BTUs output.

Can you install a 26 gallon indirect, with a platform built above it to support a boiler over top of it.

[BadgerBoiler MN]

First, a proper heat load to determine how "much" boiler you really need. The fact is, you probably don't need half the current output. Even so, a water heater is the likely solution.

Here in Minneapolis, we use water heaters for many smaller spaces that require dual purpose heat sources. Whenever a "combi" water heating application comes up, we look to storing the domestic hot water and drawing the space heating water through a heat exchanger. (The opposite of an over-sized "tank-less" or combi-boiler.

Most tank or storage type water heaters will fit in less than a 24" diameter space and rarely require and upgrade in gas or electric service. If you have to use an atmospheric vent/chimney, you will likely fine the water heater more efficient in real operation and than your old cast iron low efficiency boiler.

This is especially true if it is over-sized.