Homeowner questions about new Revolution boiler

Wayne_19

Hi Glenn,

Thanks for the reply!! The Aquastat was on 180. The installer must have moved it there. This might explain why my baseboard isn't as hot as it was with my oil boiler. I just bumped it back up to 210.

We have a Weil-McLain Indirect installed on the 3rd zone with no additional system limit that I can see that's installed. I got the manual out and the boiler limit for the Indirect is 210 so it sounds like I'm safe there.

All the pumps and spirovent are located supply side.

I'll run with the boiler at 210 and see if the house heats better. I notice the air noise a little more with the boiler at 210 but only at the boiler and it only lasts a couple minutes.

I really appreciate the help! This forum is a great resource for homeowners interested in how their heating systems really work.

Wayne

Wayne_19

Hi,

I just recently had a Burnham Revolution RV6 boiler installed in our house and had some questions on how it should be running. I'm not looking to tinker with the boiler on my own but I want to know enough to tell if things are working correctly or not.

Some background:
1845 house in NorthEast, 2000 sq ft, 2 zone baseboard heat.
Currently baseboard is undersized in half the house.
Moderate amounts of air infiltration in the house.

New boiler:
Burnham RV6.
40 gallon indirect hw on 3rd zone.
3 speed Grundof circulators on each zone.
Taco SR503 switch relay.
Spirovent.

Questions:

(1) Currently the aquastat in the Burnham is set to 180. Is this correct? I notice that when the boiler runs it gets up to 170 then stops, turns on at 150. Pressure is an even 12psi. The sticker next to the aquastat says high limit should be no less than 210. Which is why I'm confused.

(2) Grundofs are set on high on the two baseboard zones and low on the indirect hot water zone. Heat gets to all baseboards in house. Do the flow rates sound right?

(3) I occasionally notice a noise of water running in the baseboard. Especially in 2nd floor zone. Only lasts a couple seconds. Also one morning we woke up and the baseboard was warm but not hot and the house was really cold. I turned both zones off and back on and the baseboard heated right up. I suspect air in the pipes. Will the spirovent take care of this or do I need to have someone come in to purge more air?

(4) The house takes a long time to heat up. First floor zone is almost always running. I also notice the boiler cycles a lot. I would say once every 10 minutes and it will stay on for about 5 minutes. Is this bad? Would adding more baseboard make this worse or better? The house has always had a hard time keeping heat.

Our old Oil boiler seemed to heat the house a little faster than our new gas Burnham. It had a tankless coil and I suspect that the high limit was set very high ~200 which might explain why.

Thanks for any input. This is a great forum for learning about hydronic heating.

Wayne

Wayne_19

Unknown

Wayne

In answer to your questions I offer the following:

1.) The aquastat on the Revolution should be set to 210°F just as the sticker states. The L8148E that is provided on that control has a fixed stop tht won't allow it to be set lower than 210°F unless someone moved the stop.There is a reason for the high limit being set at 210°F and it has to due with the variable speed pumping that is internal to the boiler and the differential of the high limit. Setting the limit at 180°F will generally slow down the internal injection process and hinder the ability of the system getting warm and the boiler staying hot. Some manufacturers of Indirect Water Heaters call for no more than 180°F boiler supply water to their heaters, for this reason I've seen installers lower the aquastat settings to 180°F. We discuss this in the RV manual and if this is the case we call for a "system limit" to be installed on the system supply main. This is simply a "break on temperature rise" strapon or immersion aquastat that is set for a desired system main temperature of 180°F or so. This is wired into our burner circuit to shut the burner down whenever the system temperature is reached. The boiler should still be set at 210°F though.

2.) Without knowing the load calculations, I can't neccessarily answer this one. I would say that if you are comfortable with the baseboard output levels and the Indirect Heater performance, then leave them where they are. I do need to ask if the circulators are on the supply side of the system though. They need to be on the supply pipe (left rear pipe) on the Revolution.

3.) What you are hearing is captive air in the system. Depending on how the system has been piped, the Spirovent may take care of it, but it isn't a bad idea to have it purged. This is all the more reason for the circulators to be on the supply side of the system.

4.) This question is difficult to answer without knowing the heatloss of the house vs. the amount of installed radiation. The cycle times seem to be somewhat normal. Increasing the boiler limit to 210°F will shorten those on times a bit because it will allow injection into the system by the boiler to occur quicker and with hotter boiler water.

I hope this answers your questions.



Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.