Convector Install

BigRob

Just finished my first Myson convector install in a chilly SF office. This particular office is the farthest heating unit from the boiler. The manifold is piped with 120' of 1" pex. The convector is piped with about another 110' of 1/2" pex. An Alpha is pumping 1gpm on speed 3. I was hoping for at least two, it still puts out way more heat at 120F water temp than previous 2' by 2' radiator. It wasn't possible to relocate the drywall penetration, so just piped it over. The Myson 19-15 convector is ok. Pricey for what you get and it requires some additional sheet metal screws to be acceptable. I do like the auto mode that turns on the fan when water temp is >90F. Also, it remembers the last setting in case there is a power outage. We use the existing thermostat to turn on the pumps and boiler. Overall, pleased. The radiator wasn't cutting it and there was no space for a bigger one.

BigRob

Are there any better convector brands?

Ran some quick numbers and with these pipe lengths and estimated fittings, I should be running a higher gpm. I calculate about 10ft in drop. The Alpha, on speed 3 and at 1gpm, is seeing 18ft. I may still have some iron oxide in there or a ton of unexpected elbows.

BigRob

This was an in process pic. I should post the final result. After this install I found a company call Chilltrix that seems to have a much better convector for about the same money.

Rich_49

Look at Smiths PSU units and their whole high efficiency line for that matter .

http://www.emersonswan.com/ckfinder/userfiles/files/High Eff Guide.pdf

hot_rod

Jaga builds some really nice, and super efficient radiators and convectors. Their dynamic boost option is slick. Not for the faint of pocketbook.

http://jaga-usa.com/node/237


How are you getting an accurate flow measurement? Don't trust the GPM readouts on any of the electronic circulators. We have measured errors up to 60%, with lab quality flowmeters.

Unless the pump has an actual flow measuring device. I believe the Grundfos Magnas have flow reading built into the volute, not just an algorithm like most of the smaller circs use.

jonny88

is it true they stopped selling the Magna?

hot_rod

jonny88 said:

is it true they stopped selling the Magna?

Where did you hear that?

jonny88

Supply house I go to they said Grundfoss were having problems with it.Was actually looking into using one on a upcoming job.Very possible I was given wrong info.

jonny88

@hot rod magna 3 is what they said they were having problems with.I am getting Sep4 next week from manufacturer.Thanks again.

BigRob

Rich said:

Look at Smiths PSU units and their whole high efficiency line for that matter .

http://www.emersonswan.com/ckfinder/userfiles/files/High Eff Guide.pdf

Thanks for the suggestion. Check out these guys when you have a chance: http://www.chiltrix.com/chiller-fan-coil.html

I'm wondering if the convectors are re-badged Japanese units.

BigRob

hot rod said:

Jaga builds some really nice, and super efficient radiators and convectors. Their dynamic boost option is slick. Not for the faint of pocketbook.

http://jaga-usa.com/node/237


How are you getting an accurate flow measurement? Don't trust the GPM readouts on any of the electronic circulators. We have measured errors up to 60%, with lab quality flowmeters.

Unless the pump has an actual flow measuring device. I believe the Grundfos Magnas have flow reading built into the volute, not just an algorithm like most of the smaller circs use.

Thanks for the link. I was using the Rehau flow meeter on the manifold. Since that post I found more iron oxide had worked it's way down to the radiator section of the system and was clogging things up. I cleared a decent amount out but didn't check the new flow since I was pissed and tired. Another wave of work is coming and I'll update more later. I did take apart the Alpha serving the rads and there was zero iron oxide stuck anywhere in the volute, yet I am pulling some out of the SEP4. Based on my experience I don't think there is a major issue with iron sticking up ECM pumps. I know what you mean about the Alpha GPM reading. I think they really missed the mark by only using one digit for the flow indication. I mean, they have a two digit display! I wonder if this is causing the confusion. For example, if you are flowing 2.8 gpm and the pump says 2, it's pretty confusing. I've been using the watt meter display to back track to gpm. Did you all find that was off, too?

-R

BigRob

jonny88 said:

Supply house I go to they said Grundfoss were having problems with it.Was actually looking into using one on a upcoming job.Very possible I was given wrong info.

I was looking into it, too. It was on the shelf, then it wasn't. I hope the VR3452 is affordable and has an adjustable constant pressure setting:

http://www.taco-hvac.com/products/water_circulation_pumps__circulators/variable_speed_products/viridian_family/index.html

hot_rod

BigRob said:

hot rod said:

Jaga builds some really nice, and super efficient radiators and convectors. Their dynamic boost option is slick. Not for the faint of pocketbook.

http://jaga-usa.com/node/237


How are you getting an accurate flow measurement? Don't trust the GPM readouts on any of the electronic circulators. We have measured errors up to 60%, with lab quality flowmeters.

Unless the pump has an actual flow measuring device. I believe the Grundfos Magnas have flow reading built into the volute, not just an algorithm like most of the smaller circs use.

Thanks for the link. I was using the Rehau flow meeter on the manifold. Since that post I found more iron oxide had worked it's way down to the radiator section of the system and was clogging things up. I cleared a decent amount out but didn't check the new flow since I was pissed and tired. Another wave of work is coming and I'll update more later. I did take apart the Alpha serving the rads and there was zero iron oxide stuck anywhere in the volute, yet I am pulling some out of the SEP4. Based on my experience I don't think there is a major issue with iron sticking up ECM pumps. I know what you mean about the Alpha GPM reading. I think they really missed the mark by only using one digit for the flow indication. I mean, they have a two digit display! I wonder if this is causing the confusion. For example, if you are flowing 2.8 gpm and the pump says 2, it's pretty confusing. I've been using the watt meter display to back track to gpm. Did you all find that was off, too?

-R

As I understand the flow rate is a calculation based on rpm, it's not an actual measurement.

As for iron oxide, next time you pull the pump, wiggle the rotor from the stainless rotor "can" That is where the fine iron oxide powder can be attracted to the strong permanent magnet. See pic below right.

If you start getting a build up in there it drags down the rotation, eventually locking up the motor.

Any sludge you flush out, stick a small pocket magnet into it.

Here are a couple circ pumps I disassembled that were installed in our shop in Milwaukee.

The larger one, still mounted, was spitting out an error code referring to rotation impeded, something like that.

We have had 3 pump failures, the first two we were told were software problems. I wish I had disassembled those units before warranty.

I'd guess if the rotation is slowed the gpm number is off also.

The bigger question is where is the sludge coming from? I have the same concern with our system in Milwaukee, 20,000 feet of Kitec, copper piping, stainless boilers. O2 ingress should be a non issue??

BigRob

Ah, ok, I didn't look that closely- will look again. I did snap some pictures. I'll post them if I can find them. Our sludge was magnetic and I'm pretty sure it came from our old Ergomax. There must have had been a leak that was fixed before I arrived. Currently, there is no cast iron or steel used in the system, yet I keep filtering out fewer and fewer particles, which is good. I've found the seem to accumulate in elbows and radiators. Maybe you have some residual from a past component? Also, stainless does rust a little bit. If there is a little bit of sludge, could that be the source?

hot_rod

A good step on those old systems is a power flush. Really any boiler or tank change out should include a strong flush.

Either a pressure pump like a 3/4hp well pump, or a large garden hose connection. Ideally you want about 8 FPS velocity to flush heavy dirt and debris. Anything lower doesn't really move the heavy stuff that lurks in low spots and fittings.

So depending on the pipe sizes in the system, you may need some high gpm flows.

Or breakdown the system with valves to small circuits or zones to get that flow rate, one section at a time, like you would at a radiant manifold.

It's really tough, impossible really to power flush a large system with a fill valve, or even a bypass around a fill valve, typically 1/2 pipe size. Just not enough flow velocity.

This chart give you an idea of flow rates you need to get a good purge.

The engineering handbook.com also has great database to calculate flows, velocities, etc.

BigRob

Great info, thanks. I have been using a 80psi hose, which got most of it, but at high flows some sludge was getting rammed into elbows and panel radiator channels. It has not been possible to remove the radiators, instead, I reverse the flow and it usually would break free. Sometimes I had to break out the air compressor. Even so, there are still some pockets of "sand" to get out. Most is gone, especially the big flakes.

Regarding my earlier comment about the Alphas. I was reading the watts while using constant pressure modes while the pump was running in the horizontal portions of the curves. I think that is decently accurate. Maybe a pump expert can comment.

SWEI

BigRob said:

I have been using a 80psi hose, which got most of it, but at high flows some sludge was getting rammed into elbows and panel radiator channels. It has not been possible to remove the radiators, instead, I reverse the flow and it usually would break free. Sometimes I had to break out the air compressor. Even so, there are still some pockets of "sand" to get out. Most is gone, especially the big flakes.

Time for a chemical flush and some conditioner (or maybe even something like an Elysator.)