Why doesn't the toe kick circulator turn on when the zone valve is on for the same floor? What is controlling that toe kick circulator?

By circulator, do you mean circulator pump? The main heat circulator pump (the black one in the picture) is controlled by a thermostat in the main part of the house. The toe-kick heat circulator pump (the red one in the picture) is controlled by a thermostat in the kitchen.

There are two zones for this heating system, and these are supposed to operate independantly. Though as you can see by my first post, there are some conflicts between the two.

I can't see enough of any of the pipes to "see" the piping. Is the toe kick circulator (pump) installed on the return line, which I believe is the same line as the black Taco circulator is installed on.

This would subject your toe kick to cooler water than if it was on the supply line, which I believe has the gray aquastat box on it.

I'll try to take a better picture this evening. If you look at picture #2, the pump for the toe-kick heat is behind the large silver pipe. From the angle I took the picture, you can't see the pump.

The toe-kick heat pump is currently on the supply line. The second contractor recommended moving it from the supply line to the return line, and install the supply line into the main supply manifold.

He said this will eliminate the gurggling noise in the pipes.

I wonder if by gurggling, he means the slight chattering of the Taco pump due to a conflict with the Grundfoss pump?

I have a wood boiler piped in conjunction with my oil boiler and on occasion I have the same noise. It's not from air and it's not enough to bother me, but it can be heard if the house is very quiet.

However, I don't have any problem with heat transfer.

As far as air entering the system: It shouldn't be happening. Your system is closed and all air has been purged unless you have a leak somewhere and your make-up water is being used.

The first thing I would do, before undertaking any major changes is to install a 90 degree elbow with an 1/8" female tap in it right at the toe-kick. Install an air vent into the tap and that should take care of any air.

Some systems pull air through the vent or pull makeup water due to pump cavitation.

Judging by the expansion tank sitting on the bricks connected to an ultra long run of copper, the installer or whoever piped the expansion tank wasn't a professional.

That style air scoop isn't very effective, and requires an 18 inch minimum horizontal run before the inlet. Tough to tell buy the pictures, but it doesn't look like an 18 inch horizontal run before the inlet.

We almost always install quality air eliminators like a Honeywell SuperVent or SpiroVent. We use a manifold with circulators with internal flo-checks or inline flo-ckecks pumping away from the expansion tank on the supply side of the boiler. While better air eliminators are no replacement for proper piping, and isolated purges, this setup is pretty much self bleeding.

We never pump on the return side unless it's an emergency installation, space is an issue or time and money is an issue due to tight space, degree of difficulty or the complexity of repiping.

Here is a link that might be useful: Taco Air-Scoop Installation Instructions

Hello, I have added three new pictures. The first two are of the main heat pump, in the foreground. You can see the second heat pump in the background. It is red and that one controls the toe-kick heat. The third picture shows the same from another angle. Everything was running fine and quietly before the second (red) heat pump was added. Is there something about this configuration that would cause gurggling? And what would your recommendations be to fix? Thank you.

Here is a link that might be useful: Here is the link again

The toe-kick pulls water from the top of the boiler and returns it to the bottom of the boiler, as I see it. I can't tell: Is your pump on the boiler on the supply side or return side?

I believe the black Taco circulator is on the boiler return. They're using the pressure relief tapping to supply the Grundfos circulator.

I think I see the main supply line coming out of the rear of the boiler at the aquastat. It returns on the same side of the boiler. I see the supply for the toe-kick coming out of the relief valve tapping and returning to the boiler drain side of the unit.

The only problem I see, and I might be wrong, it that any air in the system would go directly to the toe-kick heater and hang there.

We haven't established if this gurgling sound is from the circulator chattering, or is it from air bubbles. So the question is: Does the toe-kick heater heat at all? Can you turn on the tstat for that heater, go down and see if the circulator is starting right away and do you feel warm water returning the the boiler on the left side? Adding a relay is easier than moving pipes. Your toe-kick should heat right away when the other radiators are heating.

You might consider adding a circulator relay to the Grundfoss pump, or adding a vent at the toe-kick to eliminate air in the line.

I heat with two boilers. I use one to generate heat and I circulate that heat to a second boiler and use that boiler's controls and circulator to heat the house. It uses two circulators and I do have a little chattering going on myself. However, I never have any problems with air.

I picked some brains today at work and they say that you need an air vent on your toe kick and a relay to start the circulator, controlled by your thermostat. Is it a wall mounted tstat? That should solve your problem.

Kristi, While there are a list of items which should be corrected on your boiler system, the main one is air in the system. The Gurggling or running water sound is the air trapped in the system. If your toe kick heater was installed properly, there should be an access panel in the bottom of the cabinet where it was installed. Also there should have been a air relief vent installed at the high point in the hot water piping. The air vent can be several different types opened either by a screw driver, coin or special square head key. If there is no air vent you can also eliminate air by making sure there is adequate air pressure in the system (typically 30 psi) at the boiler. Then you have to increase the velocity of the water thru the piping where you want to eliminate the air. This maybe a problem with your system due to the piping arrangement.

Pump cavitation is usually a swishing sound which is loudest at the pump.

Your system was originally installed with a primary (Black) pumping system which is normally sized for the boiler capacity, meaning you should not need additional pumps. The Grundfos (Red) pump is considered a secondary pump, which was installed incorrectly. It appears the secondary pump is pulling supply heating water from the top of the boiler and also past the Temperature & Pressure relief valve (T&P valve). This arrangement guarantees that air will be supplied to the toe kick heater via the relief valve opening and cold water makeup. I would try eliminating the secondary pump and piping down to the relief valve and plug the tee at the relief, then tap into the hot water supply line creating a new zone. You would also have to install balancing valves for the existing zone and new zone. By doing this you can now force water through the toe kick heater utilizing the primary pump. I would also add an air vent to the toe kick heater.

Additional things to consider correcting. In a boiler system there is a theoretical point of zero pressure. This point should be located just prior to the suction side of the pump. The suction side is a low pressure area where you should locate the "System" air eliminator (Air scoop) and expansion tank. This is also where you should be providing makeup water to the system. You should provide a tee in the bottom of the air eliminator and this is where the expansion tank and cold water makeup is teed in. You have an automatic makeup water valve which should be adjusted to always keep 30 psi in the system. Maintaining water pressure is the only way to keep air out of the system. Always bleed the air from the radiators too. Your auto air vent on the top of the air scoop looks crooked and may be hanging up too, may have to be replaced. There is a small schrader valve on top of the auto vent, try closing and opening and listen for air to come out, then make sure it is adjust slightly open to automatically bleed system air. The T&P valve relief pipe should be piped to within 6" of the floor to avoid splashing of extreamly hot water. If the relief pipe is cut at a 45 degree angle the water will flow out of the pipe more straight (Trade secret). You have a ball valve installed at the expanion tank - on the expansion pipe. This is very dangerous because if this valve where inadvertantly closed the only additional safety you have on the system is the T&P valve. If the T&P valve malfuctions too or is replace with an incorrect rating, the system can explode. If you leave this valve in place please put a tag on it stating "This valve is to remain open during system operation". Otherwise remove it, contractors put these here so when the expansion tank gives out (Leaks) you don't get sprayed while changing out the tank.

Hope this all helps.

Dan Martyn

30# of pressure in the boiler and the water make-up ????

Dan,
Thanks for your response. There is an air vent at the toe kick heater and access panel. Even after bleeding this vent, the gurggling persists.

I looked at the boiler system this morning while just the toe-kick heat was running and it was running at 15psi (and 150 degrees). I'll check again when the regular heat (non-gurggling) is running and see if it is higher.

We don't have a swooshing sound due to pump cavitation. Just the gurggling / waterfall noise at through the pipes.

Regarding your suggestion about moving the red (secondary) pump and rerouting through the main pump, that is the same solution that a heating contractor recommended. I had contacted him for a "second opinion".

Regarding the additional things you mentioned, thank you for the information. I will definately study these further and review them with the heating contractor.

With the main heat running, the pressure was at 20 psi. The pressure remained at 20 psi whether or not the additional toe-kick heat pump was running.