Taco Circulator concerns
First Time caller…Please be gentle.
We have an old oil burner - mostly all original parts. Single copper run to baseboard radiators. Output from the furnace is super hot to the touch. Return line into the furnace is warm, but certainly not the same temp. As I go around the run, I can touch the pipe on the both ends of the radiators. First several radiators, pipe is hot to the touch, but as I go around the run, its less and less, and the last unit I can hold the pipe indefinitely, with warmth, but not like the initial radiator that I can only tap before pulling my hand away.
My Taco is on the return line, just before it enters the furnace. 007-F5 unit 1/25 hp. touching the casing is as hot if not hotter than the furnace output pipe. My initial reaction was it has seized, but the more I read, the casing should be hot (140+) TRUE??
I put a digital thermometer on the furnace pipe output (About 136) return pipe into the Taco (85) and the casing of the Taco (141). Furnace is set to 180 on 160 off. during normal ops, furnace kicks on and runs for about 5 mins, then shuts off.
My rationale is I'm not circulating water. Either at all, or at a diminished rate. Rough estimate is about a 150-175 feet in total of copper, with approx 100 feet or so running along exterior walls. Before I spend the money on a new circ, is there anything else I should check? Does my logic hold water (no pun intended). Read tapping the back of the circ may dislodge any sediment that may have it jammed or diminished operations. Or does the fact that the majority of radiators running along exterior walls cool it down to warm and everything is normal. Unfortunately, the last several radiators are in the kitchen and living room thus house feels cold.
Thanks in advance for any/all advice and guidance.
Comments
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Welcome to the forum.
What you are experiencing is completely normal.
You have what we call a "serious loop". The very first radiator steals some energy from the flow to heat the first room. So, the output from the first radiator is cooler than the output from the boiler. This process repeats itself in the second radiator and the output from that radiator is cooler than the output from the first radiator.
By the time you get to the sixth radiator, the temperature of the water is down about 25°F and the output from that radiator is reduced. The Taco 007 is doing it's job. HOWEVER, if you are uncomfortable in the last rooms on the loop, there are some possibilites:
- Raise the boiler temperature to 190°/170°. This increases output in all radiators.
- Change to a larger pump than the Taco 007 that will move more water through the loop at a higher flow rate. 175 feet is a long distance for a Taco 007. The last radiator in the loop will have a higher average temperature and will output more heat. This solution only increases the output in the last few radiators.
This circulator would fix the issue regarding the lack of capability of the Taco 007:
https://www.supplyhouse.com/Taco-0015-MSF3-IFC-0015-3-Speed-Cast-Iron-Circulator-Integral-Flow-Check-1-20-HP?utm_source=google_ad&utm_medium=DSA_SKU&utm_campaign=Search_SKU_Heating_X_DSA_X&utm_campaignid=21004902424&utm_adgroupid=163851386612&utm_targetid=dsa-2277165796798&utm_product_id=&utm_matchtype=&utm_keyword=&utm_adtype=&utm_category=Heating&gad_source=1&gclid=Cj0KCQiAyoi8BhDvARIsAO_CDsAHv2_5leTpqbKhcpzxQFPlqv_6a5OIk56PRGX5M64sXa6uIeDfZzUaAl1nEALw_wcB
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The oil burner is old? And the boiler is too? That's fine, seems your issue is more toward the radiators?
Have you added any radiators to the system? Has there been recent work done to the boiler?
Do you have a air scoop or micro bubble air separate installed on the supply of the boiler?
Are you "pumping away"/
When you touch the pipes as you mentioned. A good way to tell if you are getting heat through a zone, is to feel the supply and return, at the boiler, at each zone, at about chest height as you seem to be doing.
If you cannot keep your hand on the supply because its too hot, that's to be expected.
If you can keep your hand on the return pipe, and I expect that you can, then the entire zone is not getting heat as you previously mentioned. I suspect that you are air bound and need to purge your system. Do that first before you change the circulator.
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Where are you measuring 136 degrees? how close to the boiler? you should be close to 180. You might be measuring after the flow check which would not open unless the circulator. a 51 degree delta t is big so something is not moving the water. You could be air bound. have you tried to bleed the loop?
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I put the tip of the thermometer on the external pipe joint about 12 inches or so as its coming out of the boiler, I would expect the water temp inside the pipe to be higher. I'll do it again and see if that gap closes.
As far as bleeding, I looked at each baseboard unit and not seeing a bleed valve (we had the old school radiators in my parents house in CT - so I know what those bleeder valves look like). We also vacuumed all dust bunnies out of the baseboard elements and fins. I'm not seeing any valves in the run at the radiators. It appears to be a closed loop. I'm assuming i need to do this down in the basement someplace close to the furnace. There is a discharge valve at the end of the return, just prior to entering the Taco. Crack that to see if any air sputters? Or is there another location I should be looking for the bleeder valve(s)?
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It should be a draw off, meaning it has a hose connection to attach a garden hose. There should be a ball valve or something like it that shut the return down after the draw off so you can forced the heated water thru the loop from the supply to that draw off on the return. This is provided that you have a series loop and not like a monoflo system.
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Here is the system.
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Shut the gate valve off just below the draw off. Connect the hose to the draw off and put the other end into a bucket. put the bucket in a location that it can overflow. this is so you can see the air bubbles leaving the system. the trick here is to make sure you don't lose pressure in the boiler. you need to make sure you filling the boiler back up as your bleeding. I don't see a PRV in your system
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A Taco 00 series cartridge circ pump should operate between 140-160 degrees during normal operation. To see if it is operating as it should you can take an amp reading and it should draw name plate amps. If 1.5 times more than normal amps, it could be air or locked rotor.
Please give us a call during normal business hours Monday-Friday 8am-5pm 401-942-8000 and just ask for Tech Support.
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Ok. So your gonna condemn an existing circulator that has been in system forever. Circulator that is running at its temperature so its not seized without even checking to see if the system is air bound?
I believe he said the system was 150'-175' of copper. With 100' of it on the outside walls. Not adding another 100'. I believe he means all the perimeter baseboard is 100' with the remaining to and from the boiler.
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You can check but I doubt you'll be successful.
The EL is approx. 250. You forgot the fittings.
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looks like 1” copper supply and return, maybe the loop splits somewhere, and it is not a continuous series loop of fin tube.
Looks like an older system, I suspect it has worked in the past.
Circs get real hot when they seize, but it could be the ,motor or capacitor has failed and it is not running at all?
Put a screwdriver against it, then your ear to the screwdriver, the handle end 😏, you can usually tell is something is spinning.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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I don't feel any vibration on the circ. Certainly not like be Beckett motor. I do feel vibrations on the return pipe. I assume the circ runs even when the furnace isn't firing. The other thing I find odd is the cylindrical housing of the circ is smoking hot, yet the opposite side (flow end) of the circ is only warm to the touch. Normal?
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Look at the pressure gauge your low on water pressure should be 15psi. Your under 10psi if the gauge is right.
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If its been running with no system water flowing thru it will get hot. I was thinking the same thing hot rod about the 1" and possible split loop but he stated it was a series loop. Maybe he missed it but his explanation of the temperatures kinda leaned that way.
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My numbers were based upon 3/4. If he has a split loop with a 1" return, all the values change. His initial comments didn't allude to a split loop since he commented on the last radiators in the loop.
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If it was a split loop, wouldn't I have a junction or 2nd line and circ coming out of the burner. It was one my first thoughts that maybe a valve was closed off to the living room baseboards. From everything that I can see in the basement, its one continuous loop. Even the tech said we may need to create a 2nd loop he was last here. Another thing i have noticed today, since its warmer outside and the burner isnt firing as often, is that baseboards are all cold and the copper coming out of the floor into the first baseboard is only slightly warm. Does the circ run continuously, or is that merely a matter of install and config?
I think I'm just going to resort to getting the local service folks to come out. I send him a bunch of texts and photos yesterday afternoon, and will hit them up on Monday to help resolve.
We've been in this house for several years, and everyone that sees the lengths of the baseboards in our living room comment on how efficient the oil burner is and how warm our room must be. We are in lower MD and the past few winters have been fair. This winter its been different and we've noticed a considerable difference in the warmth of the room. Plus we just had the Beckett motor replaced over the Holiday. We also shut off the burner in the summer months, so again, I assume that circ doesn't run or have any power for 6+ mos a year. I want to make this right and as efficient as possible so I'm not wasting oil on a burner that isnt warming the house.
Thanks again for all the comments and inputs. Enjoy!!
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From everything that I can see in the basement, its one continuous loop.
Can you do a few tests:
- Measure the diameter of the supply line coming out of the top of the boiler. Is it 1" or 3/4"?
- If it is 1", follow it to the first radiator. See if the pipe going into the first radiator is 1" or is reduced down to 3/4"
- Find the pipe that leaves the last radiator………..see if it is 1" or 3/4".
- Measure the return pipe in the basement where it enters the pump. See if it is 1" or 3/4".
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In older systems like that, normally the circulator runs only when the room thermostat calls for heat. The oil burner usually also runs on a call for heat, until the aquastat reaches the high temperature limit. Then the burner will turn off, but the circulator will stay on. The burner will cycle on the high temperature limit. When the room thermostat is satisfied, both circulator and burner will turn off.
As others have noted, your system water pressure is low which suggests the system may be air bound.Normal practice for 3/4" copper heating loops is to use a supply-return temperature difference of 20°F maximum, so there is a practical limit of about 70 feet of standard finned baseboard element on a single loop. More baseboard generally requires splitting the loop.
—
Bburd
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@g0vtmule Take a look at where your expansion tank is installed? I cannot see what it is screwed into. It needs to be screwed into an air separator. If it is not then you need one. Also before you start changing parts you will need to purge your system at the boiler drain and gate valve pictured near the return at the circulator. That is your "bleed area" for your system.
This is why you do not have bleed valves at each radiator. Do this first and see how the system reacts, especially if the system has been fine till now. Doing this correctly is the place to start. After that we can get into what should come next.
P.S. Post a picture(s) of what the expansion tank is screwed into. A couple close up.
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amp meter reading will shed light on what’s going as Steve from tech support suggests. You should at or close to nameplate amp on demand. 1.5 times nameplate it’s locked rotor and cartridge requires replacement. If it’s less than nameplate your airbound, pump is running and not displacing water. You’re probably getting some flow through thermal siphoning. Check valve should minimize thermal siphoning and depending on capacity of adjacent zone pump, it’s possible to overcome pressure differential to allow flow into that zone.
Contact Taco tech support at 401-942-8000 for further assistance.
Joe Mattiello
N. E. Regional Manger, Commercial Products
Taco Comfort Solutions
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This is also assuming the pressure gauge works. So many are stuck on a good reading, but are actually at zero.
I would do the amp check on the motor, and also check the pressure with another gauge.
Rick
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As requested. The black knob on the valve is broken. Can see it best in the 2nd picture.
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Jie. Thanks for your response. I'll reach out to tech support to get guidance on where I'm placing my Fluke probes
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Thats a Fill-trol tank. You are going to need to drain the boiler pressure from the boiler and check the air pressure in the tank in order to make sure it's filling the boiler to the correct pressure. There's also a screen on the inlet side of the Fill-trol valve that tends to get full of sediment if it hasn't been cleaned.
Voltage and amperage measurements will confirm if the circulator is an issue. I wouldn't be surprised if boiler pressure isn't the problem.
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And your picture you supplied verifies that you do not have an air separator. You need one. Google the Spirovent company.
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