swapped out taco 007 for basement hot water loop off a steam boiler same results!

skimmer

I just swapped out a taco 007 circ pump for my basement hot water loop. I suspected a flow problem. Basically tstat is set at 70 and the boiler cycles off and on and pump would run constantly. I had upped the aquastat to 200 last year to try and get more "heat" into the loop.

I pulled out the old taco and it was badly corroded, and i thought this would solve the problem. However after the new one was installed it seems its doing the same thing, constantly running, tstat set at 70.

skimmer

i bought these clamp on pipe thermostats

this is the temp right after the circ pump, and I have the aquastat set to 185

this is the temp and the other end of the loop right before it goes back into the boiler.

Im not sure how accurate these things work

skimmer

Im scratching my head here.. Im thinking maybe the flow check is badly corroded and causing a flow issue? Its right after the pump and before the first pipe clamp thermometer

any help appreciated

skimmer

Well it just shut off, it took about an hour to satisfy the tstat. Its 47 outside in nyc. and its heating basement convectors first one running thru a garage. Not sure what to think. I thought hot water heating would heat up pretty quickly , the first rad feels like it barely puts out heat.

LRCCBJ

The first thing that must be resolved is the two temperature readings that you provided.

At what point in time did you take that photo? Do you have any idea how long the boiler was running when you took it?

You should have the temperature of the boiler at or close to 200F…………..and, yet, the thermometer reads 160F……………..

I'd like to see a photo after the boiler has been running for at least 15 minutes. If this is the situation, either the aquastat or the thermometer is suspect. It's hard to quickly warm a space with an average water temp of only 150F.

BTW, you can get your mind off flow rate. The DT shows you have sufficient flow.

Jamie Hall

There are all kinds of considerations here. But first, you have about a 20 degree delta T, so as @LRCCBJ said your flow rate is probably about right for the radiation being powered.

Further, it is likely that you are getting about as much heat out of the radiation as it can provide. Increasing the input temperature will get more heat out of it; if the flow rate stays the same you will see that as a bigger delta T.

Now you seem to imply that this is a series loop, with the first emitter in a garage. That first emitter will be producing the most heat, and the rest going down the line will be producing the least.

skimmer

so this is a burnham steam boiler and no heat was being called for on the steam side.

This pic was taken after it was running for about 45 minutes. Cycling on and off on the aquastat I presume bc the circulating pump was constantly running. I had it set for 180 initially and bumped it up to 185 and it seemed to raise the temp a tiny bit on the clamp thermometers.

This was done today and the boiler had to be filled with fresh water as it lost a lot from the pump change. So this was a cold start but once the aquastat hit 180 then the boiler shut down at least that’s what it’s supposed to do?

I also used a laser thermometer but the temp was bouncing all over the place. I think the pipe surface and the quality of the laser tool don’t help.

I also opened the valve and got some of the water into the bucket. I believe I got a higher temp with the laser tool. Maybe that’s a better way to get an accurate read.

Do you think it’s a bad aquastat?

EBEBRATT-Ed

Determining if you have enough flow, too little flow or a restriction can be confusing. Maybe the flow check is sticking, and you can try taking it apart and cleaning it or replacing it.

Seems you probably have a restriction can you flush that loop?

Where is the other boiler connection.

skimmer

yes I can flush it via city water pressure. Did that a few weeks ago. Got a nice flush out.

Here’s a question. If I call for steam heat then the water temp in the boiler should be 212 degrees once my upstairs radiators start steaming…

At that point if the taco is running i should see the 200 degrees at the copper pipe where the first strap thermostat is located , just after the flow check?

skimmer

here’s the return on the loop. I’m out so it’s a pic from a couple of weeks ago

Jamie Hall

The temperature of the water leaving the boiler — even if it is steaming, but especially if it isn't — is determined in large part by the circulation of water in the boiler. It is unlikely that the entire volume water in the boiler will be at the same temperature (in fact, if it's steaming, you rather hope not…).

hot_rod

are you sure it is circulating

Maybe some air bubbles are in the piping?

skimmer

I hope it is. Just put in a new 007.. I don’t have a way to test the flow other then to put a discharge hose on and start the pump and see if the pressure kicks on.

Pretty sure it’s circulating as the temperature does increase at the end of the loop.

I’m guessing it’s the aquastat. Maybe the bulb? I can adjust the wheel upwards and see if temp rises.

but if it’s steaming. Then obviously the boiler water will be hotter. Taking the aquastat out of the equation for the test. The only other thing I can think of it’s the flow check.

The boiler is 4 years old but I’m thinking that the pump, flow check and aquastat were reused. Making them 20 years old

ethicalpaul

It is unlikely that the entire volume water in the boiler will be at the same temperature (in fact, if it's steaming, you rather hope not…).

I think it's pretty likely to be pretty close. Especially if it's steaming since the bubbles will form at the bottom and carry up through the rest of the water, constantly mixing it.

Jamie Hall

Depends a lot on the actual boiler design and the location of the tappings, @ethicalpaul .

Big Ed_4

Flush out the loop and open the flow check which is not needed and can jam up in a steam system .. Best to pipe the manual feed to the condensation loop . You can then purge and flush out the loop the loop…

skimmer

open the flow check. Turn it all the way counter clockwise if I read correctly? Can I remove it completely?

mattmia2

Could you move the thermometers to near the emitters so that they are far away from the boiler? I'm concerned that with little or no flow you're still going to be heating that section of pipe close to the boiler by conduction and convection.

Big Ed_4

Turning the top knob counter clock opens the valve or unscrew the bonnet and remove the weighted seat .

EBEBRATT-Ed

Does any portion of this hot water loop rise above or near the boiler water line? You can certainly open the flow check to try it but you need the flow check to make sure the HW loop does not overheat when running for steam.

If any part of the system is above the water line your probably air bound

109A_5

Hello skimmer,

Did this basement / garage hot water loop ever work correctly ? Is the garage part above the boilers water line ?

Long Beach Ed

As Hotrod and Ed point out, this can be air bound. I've had lots of trouble with basement loops where a slug of air surrounds the pump. You say you can flush this at main pressure. Make certain that the loop is filled with water. Any high spots can accumulate an air bubble. And what's that drop in the copper pipe before the return meets the boiler ? That's no good.

If this ever worked, I suspect your issue is with air or the flo-check valve.

That copper in the photo looks higher than the Hartford Loop. If it's above or very near the water line air is your problem.

skimmer

none of the convectors are above the water line. Everything is below. Perhaps at the last bit where it returns to the boiler it may be at the water line depending on the water level of the boiler

hot_rod

did the new circulator have a check valve in the discharge? If so you could remove the flo check

STEAM DOCTOR

Did this ever work? In my opinion, you don't need any sort of float check. I never put one in these setups, and never get gravity flow

skimmer

the new circulator does not have an internal check valve. Yes this did work.

I do stand corrected. The stat is set to 70 and prior to today’s replacement the boiler would constantly run.

Now it doesn’t seem to run constantly. It could be bc it’s mild out. I don’t always have access to the basement area (it’s rented out) only I have access to the garage where the first convector is located.

So at the moment there is an improvement. Although the pipe clamp thermostats indicate a below satisfactory water temperature. I will have to flush out the loop to eliminate air and also adjust the aquastat higher. I’m thinking that maybe it’s not working at the temp it’s showing.

Further testing will tell. As the outside temp drops it will be easier to adjust and test. Once this boiler is running and making steam at 212 I should at least see close to that temp at the first thermometer, and then compare what I get at the end of the loop on the second thermometer.

also I have gate valves. One near the beginning of the loop and one at the end. I can open and let some water out into a bucket and use a digital thermometer to get the temperature readings from both locations. That might be more accurate?

109A_5

Seems odd to me sending the heat to the garage first, then the living space, although the garage probably needs more heat if you actually wanted to keep it at a comfortable temperature all the time. I probably would have zoned them separately.

skimmer

yeah I don’t know why. It was installed in the 1980s. They just ran it out thru the garage around the basement which was used as a home office, thru a bathroom and back to the boiler.

The garage is under my living room so I guesss the bonus is a warm garage equals a warmer living room..

I have one convector in the garage and the rest of the copper pipe has been insulated with foam pipe covering

mattmia2

Why did you replace the circulator, was it seized or otherwise bad? If there are any leaks above the water line it can let air in and cause it to get air bound. I wonder if the emitters are mostly a pocket of air with a little water flowing through.

pedmec

when you did the flush did you flush the loop or the boiler? you need to have isolation valves on the supply and return and boiler drains on the supply and return so you can hook up a garden hose and force water thru the loop and bleed it out the other side. Steam systems are extremely dirty and sludge will settle in the baseboard and reduce heat output

ethicalpaul

some or all of the loop can be many feet above the waterline.

As long as there are no leaks, then no air can get in and it will never be air bound once it has been flushed.

I have one loop on the basement ceiling and one loop 9 feet higher in the second story’s floor

SuperTech

https://forum.heatinghelp.com/discussion/comment/1821686#Comment_1821686

Just wondering how you accomplish this without any water pressure. It's my understanding that water pressure is needed to overcome the difference in elevation between the boiler and heat emitters in a hydronic system. On a steam boiler you don't have any water pressure.

ethicalpaul

the downhill side “pulls up” the uphill side with the help of the circulator. You have to fill the loop with water first.

Read about it in Dan’s article here

LRCCBJ

https://forum.heatinghelp.com/discussion/comment/1821523#Comment_1821523

Firstly, it is highly unlikely that you have a problem with flow. Your supply is at 160F and your return is at 140F. This cannot happen if there is insufficient flow. The return temp would be in the teens.

Turn the aquastat up to 210F.

Run the boiler for at least 20 minutes with the thermostat calling for heat at the zone.

Take another set of photos of the temperature gauges.

We'll see if that aquastat is reading low.

BTW…………you don't need a new aquastat………….just a recalibration of this one.

skimmer

ok I will try that later on and post my findings

thanks to everyone for their insight

mattmia2

I'm not at all convinced that the gauges are reading the temp of the water in the loop itself where they are located.

skimmer

the first garage is about a foot away from the circulator pump before the 3/4 copper pipe goes under cement to the garage

the second gauge is at the end of the run right before it enters the Hartford loop to return to the boiler. Again strapped to the copper pipe

EBEBRATT-Ed

Yes you can run a condensate water loop with a circulator up above the boiler water line, but you have to follow certain rules.

Everything has to be 100% water tight

no air vents

You have to isolate the boiler and fill the loop and flush all the air.

Then open the valves to the boiler. All boiler connections must be below the water line.

Dan describes this in one of his books, forgot which one. Maybe "How Come".

Big Ed_4

The condensation loop is a cheap way to add heat a finished basement . Below the water line , just flush out the mud and replace circulators now and then. If you want to heat the higher floors, add a heat exchanger and water pressure to the hydronic side…

skimmer

ok update.
Aquastat set to 210 and system running for over 30 minutes. Doesn’t seem to make a difference on the temp gauges, maybe a 5 degree increase. Only seems to make the boiler cycle on more

Gauge at the start of the loop

gauge at the end of the loop return to boiler

LRCCBJ

There is something seriously amiss with the gauge at the start of the loop. It is virtually impossible to have that gauge read 161F, the aquastat at 210F, and the return water temperature at 160F.

I never had confidence in the strap on gauges.

Get an infrared gun, put a piece of black tape around the pipe near the supply gauge, and shoot it to confirm the real temperature. My bet is that you get 185-190F.