Circulator help please

Hi Guys- long story short had to reregister under this name since its been too long for my password to be saved. However- here is the situation.

I have a Biomass 40 boiler that pumps out to the heating loop by way of a Taco 0010.
At the loop I always had in the past to partially close down the ball valve between the boiler feed to the loop and its return to get any circulation through the loop. Each zone has its own Taco 009
Now, the colder it gets the more I have to fiddle with it and shut off zones to get any heat. Basically with this real cold weather I have shut down several zones and use a wood stove. It seems that this year is even worse when I replaced a 007 circulator on a zone.

I have made sure there isn't any air in the system and tried to get information on why it is working this way.
I ran a test with the propane boiler with a taco 007 circulator that is right next to the loop produces enough to run every loop with enough heat.

Its obvious to me the 0010 circulator isn't producing enough pressure head or flow to work correctly. I ran the TACO pressure calculations and they show the 0010 should work, but they don't account for the Termovar mixer. I need to replace the circulator with something better.

I looked at the TACO flow and pressure charts, and a 0012 and 0014 would have enough pressure and flow, but then I have to worry about too steep of a pump curve. So I'm looking for advice about the replacement TACO or using a three speed Grundfos or Grundfos Alpha in this to match up requirements better.

thanks for the advice in advance!

Information change- no thermovar, its an Ebse TV mixing valve. By way of illustration, the heating loop is a rectangle shaped loop that has all the individual zones coming off it. The propane boiler also is hooked up to this loop in the same manner and has no problems circulating the hot water through the loop. The wood boiler has a 15 foot or so feed to the loop and the same for a return.

Boiler gets up to heat without any problems, and the 15 foot pipe running to the heating loop is very hot. The return is only warm at best and there is no flow through the heating loop unless I close down the valve between the output and return to the wood boiler. Changing the position of the ball valve that feeds the direct line line back to the mixing valve has minimal effects until it shuts off what circulation I do get.

I did have a 120 degree thermostat that I popped in the mixing valve and I took out the 160 degree thermostat. When I did that the boiler wouldn't come up to temp unless the feed to the heating loop was shut down. So I switched it back. I m getting in a new 140 degree stat that I will try this weekend to see what that does.

FWIW- I do hear a noise from the pump that makes me wonder if I hear cavitation. Sounds like a grinding noise that comes and goes

Honestly I don't think the pump was doing a proper job on day 1. I have a theory that it was underpowered from the start, and due to several years use it has gotten weaker every year. What got me going on this though was that the small circulator from the propane boiler that is right next to th loop has no issues pumping to any and all zones at the same time. This circulator by the pump was never able to match it.

I am pretty sure there isn't an air pocket in there.

When I shut down the valve on the heating loop between the intake and output of the wood boiler there is a strong suction as long as a zone is calling for heat. No heat call, very little to no circulation. Furthermore, the highest zone in the house will not get heat from the wood boiler, yet it does on the propane.
Hence my belief that the zone circulators are doing the job of circulating the water around the loop where they can, and the pump isn't doing its job.
Rather than replace the pump with the same one that didn't work all that well I want to upgrade the pump.

However, I am aware I may be completely wrong in this assumption.

This is a photo of the pump and Esbe mixing valve. The bottom feed is from the heating loop. The side feed is from the tee and ball valve connected to the boiler output to the loop. The top is the feed to the pump and then to the boiler.

This is a photo of the feed and return to the loop from the boiler. The bottom lines are from the wood boiler and the feed is on top. Note the ball valve has to be closed half way to get any circulation in the loop. The top lines are from the boiler and the circulator is right there.

Last but not least phtos of the heating loop. Each zone has its own circulator. Every zone has its own feed except for the mixing valve on the left that feeds two radiant heat zones, but all have their own circulator and return. I had to turn off the radiant in the middle to get some flow to the radiant already discussed.

Fred61 said:

A little confusing to me too.
The pipe connected to the center tap of the Esbe should be teed off from the supply output on top of the boiler. There should be a throttling "valve"in that line to control the flow to the esbe. Throttling the heat loop is not the way to control the flow from the boiler if that's what your description and what I see in the photo is implying.

That is how the Esbe is set up with the supply to the center tap There is a throttling valve there that does control the flow. And you are correct in that I have to throttle the heat loop to circulate.

Also, is the Esbe oriented correctly? The bypass flow must be hitting the bulb side of the automotive thermostat when temp is below thermostat value.

Click to expand...

There is only one way top insert the t stat into the esbe's bronze holder and it orientated so that the bypass flow hits the spring section of the t stat- this is correct I think.

I believe the Esbe is the root cause of the issues. Yes the circulator is going, but maybe the Esbe caused it to be overworked. I do have to leave the throttel mostly open to the Esbe to get any flow out to the loop... perhaps this diverting the majority of the flow is creating the pressure problem in the loop?

Here is it Pic 1 is the whole loop by boiler. The tee from the output goes down the pipe and into the side of the esbe. The circulator has a shot off above and below it, and then turns 90 degrees to go directly into the boiler.
pic 2 is a closer pic of the tee and throttling valve.
pic 3 is a closer pic of the bottom where it all goes into the esbe
pic 4 is where it comes out of the boiler and goes into the piping.

So here's my update. The 160 degree thermostat arrived and was installed. I turned off the restriction on the heating loop between the intake and output from the boiler and there is strong circulation. The heating loop for the zones is real hot and the circulators for the zones all appear to be working.

However now the boiler won't get up to temp. However, when I attempt to close the ball valve that runs from the output tee to the Esbe, there is a loud whistle or screech sound. So I open up the valve half way but the temp doesn't go high enough on the boiler.

Also, by saying bulb you mean the spring section of the T stat? The spring section is what I have inside the Esbe in the boiler bypass flow

I turned off the largest radiant floor section and the 140 degree stat kept the other zones doing well during the night. and the boiler got up to temp. It went to 8 degrees last night too. Even the furthest and highest zone had enough to going through it to easily keep up with the cold.

Observations- the new stat, while it wouldn't get up to temp with the total demand of the house, did so with the largest heat loss area turned off. With this heat zone on, everything was still working (and keeping warm) but the boiler itself wouldn't get up to temp. I put the ball valve that was between the boiler input and output at the heat loop back to no restriction when I replaced the old stat and everything worked well.
The circulator that I was looking to replace is much quieter also.

I wonder if the original stat I got with the boiler was bad and caused my issues? With the new stat there is enough pressure and heat to run the entire house (but the boiler doesn't get up to temp), and this stat is 20 degree lower than the one that the Esbe comes with. Needless to say, I ordered a 160 degree stat for 7 bucks online that will be here Tuesday to try out.

Any idea what the squealing sound in the pipes when I adjust the throttling valve to close down the flow from the bypass to a slow trickle to the Esbe means? I am currently about half open with this throttling valve. I did notice that when I turned down the ball valves by the circulator at the boiler this sound from the pipes stopped....