hydronic loop on steam boiler

Mannu

My steam boiler, Weil McClain EG-55, only has a tap on one side, no tap on the other side. Can i still run a hydronic loop with a heat exchanger?

https://www.weil-mclain.com/sites/default/files/field-file/EG EGH Series 5 Boiler Manual 0117.pdf

EBEBRATT-Ed

Probably. You have to be creative. You may have to tee into the condensate return or a drain connection or use a double tapped bushing. You may be able to make it work without a heat exchanger in some cases

Mannu

I only have a drain connection on the one side, the manual says it has a opening on the other side that i could tap but the sleeve doesnt have any perfs on it to get to it. Was going to use a heat exchanger to have a closed system to make life a little easier.

EBEBRATT-Ed

get the boiler manual it will show where all the tappings are

Dave0176

The EG series boiler has 2-1/2” return tappings on both sides, the one side is just plugged and the boiler jacket hasn’t had the knockout removed. It’s there.

DanHolohan

This will help:
https://heatinghelp.com/systems-help-center/how-to-run-a-hot-water-zone-off-a-steam-boiler/

Mannu

would i be able to run 2 hydronic zone loops off this steam boiler with a heat exchanger or will that be too much?

DanHolohan

It depends. From that link I gave above:

Q: How many hot water zones or indirect heaters can I take off a steam boiler?
A: That depends on the boiler's capacity. You can't take out more BTUs than you put in. I've seen people try to add one too many hot water zones and when it came time to make steam, they were out of luck.

Q: What's a practical limit for a house?
A: Again, a lot depends on the size of the boiler. Usually, you can get away with a 3/4" line, flowing about 4 gpm. That'll deliver 40,000 BTUH, or so to the zone. That's enough to heat a good size zone.

Q: Will I always be able to get 40,000 Btu/hr our of a residential boiler?
A: Yes, if the boiler's net load is over 120,000 Btu/hr.

Q: How come?
A: Because you're playing with the boiler's pick-up factor. The pick-up load usually represents about a third of the net load, depending, of course, on how the installer sized the steam boiler. One-third of 120,000 Btu/hr is 40,000 Btu/hr. That's equal to 4 gpm, about what you can expect to flow through a 3/4" copper line.

Q: What is the purpose of the pick-up load?
A: The pick-up load gives you the "extra" capacity the boiler needs to heat the pipes as the steam heads out toward the radiators.

Q: Is the pick-up load always available to me?
A: No, it becomes available to your hot water zone only after the steam pipes have heated up.

Q: How about if I'm not making steam?
A: If you're not making steam, the pick-up load (and the rest of the boiler load) is obviously available to your hot water zone.

Q: So the pick-up load sets the limit on what I can do with this zone?
A: Yes.

Q: Let's say I'm sizing a new steam boiler and I want to use one or two hot water zones. Should I add the Btu/hr of the hot water zone into the Btu/hr load I need for the steam system and then select a boiler for the combined total?
A: No! Never add the hot-water-zone load to the steam load when you're sizing a replacement steam boiler. This is a game of subtraction, not addition. Size the steam boiler first. Base it on the connected steam radiation load, plus a suitable pick-up factor, not the heat loss of the building. Then work with the available pick-up load to size your hot water zone or zones. You can't take out more than what's there.

Q: What happens if I over-size my steam boiler?
A: You'll have problem with the steam side of the system: surging water lines, water hammer, uneven heat, high fuel bills.

KC_Jones

What is the heat load of the space you are trying to heat?
What size is the boiler (EDR rating)?
How much EDR is connected to the steam boiler currently?

Mannu

ok so change of plan, can I do two zones with the tankless water heater coil? Won't be using a heat exchanger no longer.

KC_Jones

What is the heat load of the space you are trying to heat?
What is the output of the tankless coil? If you don't know that post pictures of the tankless and someone might be able to figure it out.

Mannu

One last question, my boiler does have 2.5 trappings on both sides. So the current return is tapped on the right side. The left side isn't used and the drain tap is on the left side as well. So the question is can I tap into the current return for the loop return? If not, can I use the other side as the return and the drain to send water out to pump?