Alpha 2 pump <4 months old now has noise

swellman

We recently converted our system into two zones (basement and upstairs) using two newly purchased Alpha 2 15-55 pumps. This was ~3-4 months ago. A couple weeks ago, we noticed that often when the basement pump comes on and is up to speed we hear a noise that can be heard at the pump and from the radiators. We never hear it from the other upstairs pump. I have a clip of the sound but it seems we can't attach mp3's here... maybe they work through messages if someone is interested? It sounds kind of like water/air swirling. I've tried bleeding the rads downstairs and upstairs 2-3 times with the exception of two rads which don't have bleed valves.

The noise is definitely distinct from how the pumps sounded at first because (1) the two pumps now sound different from each other and (2) we can hear it echoing at the radiators. Usually it only last a couple minutes and then it's over... until next time. It probably happens ~10-15 times a day? I'm also not sure if we hear it in our unit upstairs only when our pump is also running or anytime the basement pump is running regardless of the status of ours.

The basement pump is set to AutoAdapt mode. It runs at ~6 GPM and 20 Watts when fully up to speed. The upstairs pump is also set to AutoAdapt and runs at max speed.

The temperature of the pump's pipe where water is running through reads about 150 Fahrenheit (laser thermometer read) before the high limit switch of the boiler kicks in to shut the flame off (it's an old raypak with a single full 110Btu flame setting). The pump continues to circulate so long as the thermostat calls for heat.

Any ideas on what could be causing this noise?

HomerJSmith

You mean an Alpha 2 15-55 pump. A pic of the boiler and pump connections would help. I have never had noise coming from an Alpha pump. Something else going on here?

Solid_Fuel_Man

Do you have a magnetic dirt trap? 

What does the water look like?

Are you pumping away?

I assume this is a cast iron radiation system. Was it flushed?

What pressure is the system operating at?


My guess but your description is that the pump is running full tilt due to cavitation from either a low pressure and exasperated by pumping toward the ex tank. And it's full of magnetic gunk.

swellman

@HomerJSmith - Sorry, Alpha 15-55 is right. Thanks!

Here is a picture:

We have an old style expansion tank hanging in the ceiling. When we re-piped the supply area for the two zone we asked around about changing to a diaphragm tank but in the end the consensus was to "let the sleeping dog lie". The pipe connecting the expansion tank into the rest of the system is hidden inside the boiler itself but is beside the return line (to the left of the return line in the photo).

@Solid_Fuel_Man:

No magnetic dirt trap.

The system has been drained and re-filled 4-5 times in the last year to solve leak issues/change piping runs/make it a two zone system. Last time I saw the water it was reasonably clean-looking running into a bucket but it's possible some of the cast iron rads themselves still have some sludge material in them anyway? The house is ~110 years old.

The system is all cast iron rads on the upstairs zone and primarily steel on the downstairs zone (two small cast iron ones in the basement still). The steel ones were all added in the last year to provide more heat to the basement as part of the two zone system.

Pumping away... Probably not? How the expansion tank exactly connects in our case is not clear but it does look to be plumbed in on the same side of the boiler as the return as opposed to with the supply. This was our #1 reason for asking here about changing the expansion tank but the best advice we got was to leave it as is.

System pressure is ~16 psi right now.

------

Not asked but some other data points:
- Noticed our rad temps seem to not have any real temp differential right now. Thoughts if this could be connected? Should I slow the pump speeds down and take it off auto adapt?
- Our upstairs pump runs ~43 W on high speed.

mattmia2

Where is the air valve that captures the air in the system and returns it to the expansion tank? A magnetic dirt trap would be a great idea on that system, especially with those pumps.

PC7060

Can you give us some more pictures of the boiler piping? 

I’ve got an alpha two in my system pumping into a old school cast iron radiator system from a HTP UFT boiler.  I found that on auto mode the circulator moves too much water and I get noise in the system. I ended up setting mine for a constant speed at level one and it all works perfectly quiet.

Do you know if system is configured for a direct pumping out of the boiler ir is it configured with primary secondary loops?  

HomerJSmith

I had pump that was making too much noise, so I bought a set of ear plugs--problem solved! --- O.K., that's a joke.

"Let sleeping dogs lie," hmm! Model T Fords were a great car, but I don't see many of them on the road, today. Replace the static expansion tank with a newer design diaphragm tank and for 'Pete sake' put a Dirt mag on your sys with an air eliminator if you don't have one.

Yup, I flushed the sys. Err, drained it 4-5 times. That doesn't cut the mustard. In order to remove solids in a sys, one need to move water at 5'/sec to get solids out of the sys. You need a pretty good pump to do that. If you did that, you would be surprised at what came out of it. Probably a lot of Iron debris. A good flushing on an old sys, when ECM pumps are put in is well worth the effort regardless if you installed a Dirtmag, especially when there is a lot of iron in its construction as is yours .

I always sit the customer down and have a heart to heart with him. I hate coming back and re-fixing a problem that wasn't addressed in the first place.

swellman

@HomerJSmith - isn’t city water pressure which is used to fill the system moving above that speed even? Or are you saying it might move everything around quickly but the actual drain speed is obviously not of the velocity I need to move it *out* of the system? To do the ‘flush’ you’re talking about is it as simple as hooking up the city water in a way that bypasses the pressure regulator (I have a setup for this) and then letting it work through the whole system while the drain is open so that it is pushed out the drain? 

I haven’t heard of the dirt magnets before. I’ll have to look into that. I unfortunately don’t think I have the space required for the air separator and the diaphragm which was another element that held us back from changing out the old expansion tank. 

@PC7060 - It’s curious. It’s on my zone with the steel rads that I’m getting the noise as opposed to the cast iron rad one. I’ll try lowering/setting a constant speed on the circuit though and send the update. If it does lower the noise, how do I be confident the speed was the problem as opposed to the pump just running more quietly at the lower speed and therefore more difficult to detect a sound that in reality is still there and signalling a different problem? 

Also, we have direct piping (correct me if I’m wrong but that’s where the supply line goes directly to the rad and then the rad has a second line which just goes and joins directly into the return rather than going on to the next radiator right?). With one exception. There are two rads in the basement that are in tandem. Water flows through one and then the other and then joins back into the return line. 

mattmia2

Ok, i'll ask again. Where is the air control for the conventional tank that separates the air that works its way out of the conventional tank and returns it to the tank?

HomerJSmith

swellman, the answer is No. I will give you an example from my recent post. I was working on a sys, where the pump was oversized which created high velocity in the piping sys to the manifolds. This eroded the copper pipes and left a copper sludge in the 1-1/4" pipes. I fixed the flow problem and flushed the sys until the water was clean with street water pressure just to get the heat going. I went back and flushed the sys with my high head 1hp pump and the debris just poured out of the sys. I will give it another flush when I install Caleffi Twistflow manifolds replacing the old Wirsbo manifolds.

You can put the expansion tank where you have room, just connect it before the sys pump.

https://www.supplyhouse.com/Caleffi-546197A-1-1-4-Sweat-5461-Series-DISCALDIRTMAG-Air-Dirt-Separator-with-Magnet

PC7060

The steel radiators have a higher resistance to flow of water (aka higher “head”) so that zone would be potentially noisier under high flow rate. 

What GPM does the Alpha 2 display for the two zones. 

Does the temperature of the boiler go down when you have call for heat on zone with large cast iron rads?

A direct system is on where the pump pull (or pushes) water directly from (or to) the boiler.  

Can you sketch the layout of the system?  

What kind of boiler is this?

swellman

@mattmia2 - Sorry I missed responding to your comment. Honestly, I'm not entirely sure if I know. The earlier picture shows it is shared with the drain line and is connected inside the boiler keeping it hidden exactly how it connects to the other lines. At the expansion tank itself it looks like this:



The device with the knob is a check for whether the tank is waterlogged. Basically, turn it and if there is water then the tank is too full.

swellman

@PC7060 - Alpha2 readings:

When basement pump on by itself: 6 GPM // 20 Watts
Basement when both pumps are on: 4 GPM // 14 Watts
Upstairs pump: Runs on "HI" // 43 Watts (regardless of whether basement is on or not)

The boiler is a Raypak 135 WT. Here is a photo of the inside label:


The boiler has a single "heat" setting. So regardless of which zone/both is/are calling for heat, it's putting out the same full BTU capability. Our temperature reads up to ~150 F at the pumps at which point the high limit switch kills the flame. Upstairs at our rads it reads ~100-110 F. It does seem that both at the rads and at the boiler supply/return lines there is almost no temperature differential. Should I consider slowing down one/both pumps? 

I can sketch a layout of the system. Will come back and post!

swellman

@PC7060
Here is a map of the system using our basement floor plan. Note that I'm not 100% sure of exactly how the second floor rads tee off the other main floor rads/pipes which is why there are some question marks. But upstairs there are a total of 5 rads. One in each of three bedrooms, and one in each of the two bathrooms for a total of 5.

PC7060

I can't imagine why you would need to pump that much water through those cast-iron radiators.

I’d try a constant speed setting of 2 on the upstairs zones to see if you can get gpm into 6-8 gpm with a measurable temperature drop. May need to drop down to setting 1 like I had too; best to move less water so you get high delta T with return. 

Sounds like you’ve got a old school cast iron boiler which turns on when water drop below a certain temperature in the internal tank. Call for heat from thermostat engages the pump only. Minimum flow rates aren’t really an issue as long as system is keeping Zone is warm. 

That’s the nice thing about the Alpha, it’s easy to change and provides handy GPM/wattage information. 

mattmia2

I think there is supposed to be an air control fitting on the boiler piping that is connected to the tank which sends any air in the system to the compression tank(looks like it is a special fitting where the tank connects to the system). It is like an automatic air vent and air scoop but it sends it to the tank instead of removing it from the system.

When you purge the system you introduce fresh water with air dissolved in it. As that water is heated the air is released so either you need an automatic control to remove it or you will need to bleed it out. Some of the air in the tank will also dissolve in the water and migrate around the system and collect places.

Th fittings are described here:
https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1303145247455/53802_PROD_FILE.pdf

Canucker

@swellman Is your Raypak a cast iron boiler or copper fin tube? I have the same design in my basement with multiple zones, copper fin tube. It has primary/secondary because the boiler needs a minimum flow rate through it at all times. Your system is direct pumped, so I would be careful turning the speed of your zone pumps down unless you know the flow in each separate zone is enough for the boiler.

Dave H_2

This is not an air or pumping issue, these little pumps will not likely cause cavitation.

This is a magnetite issue; cast iron boiler, iron pipe, cast iron rads........lots and lots of magnetite (rust)

Yes, it was drained and flushed a few times, but all that does is stir it all back up and with all of that new oxygenated water, create more rust. The circulators that you have installed have a magnet as part of the rotor and no protection and the rust is gathering at the internal bearings and making the noise.

A standard AC circ is needed or a magnetic dirt separator installed.

swellman

@ Dave H_2 - This is an interesting hypothesis. Is the magnet in the pump only functional when it’s running or always magnetized? I.e. could magnetite be expected to fall off while the pump is off? We don’t hear the noise all the time. I’m wondering if it’s possible we have a pump on (“magnetite collection time”) and then pump off (“magnetite drop off time”) relationship that might explain some of the coming and going of the noise (eg we only hear it once it’s collected x amount of magnetite). 

One other thought maybe you could comment on is the fact only one of our two pumps make the noise (basement). The differences I can think of between the two pumps is (1) basement runs more often and (2) water has to come out of the boiler and go through an elbow before reaching the basement pump. Water coming out of the boiler goes straight up into the upstairs pump. Perhaps the elbow under the basement pump is a nice ‘magnetite drop collection point” and makes it easy to pick up again in the basement pump? 

Also, just a mid-way point of thanks to everyone who has taken time to comment and think about our problem. I really appreciate it. We have found this to be such a great radiator forum! 

swellman

@Canucker - I don’t think it’s copper fin tube... the lines all feeding in/out directly at the boiler are cast iron and the boiler housing itself I don’t think is copper metal. Is there something else that would clearly tell me? It does have “fin” like vents in the front and is a painted a “cool” blue-green colour

mattmia2

That offset may give air someplace to collect then get sucked in to the pump when it turns on.

Dave H_2

The magnets in ECM circs are always "on" ; it's not an electromagnet, the rotors are manufactured that way.
Some ECM circs have a barrier to prevent the magnetite from getting to the bearings.

Why one over the other right now? Maybe one has "seen" more run time over the other and has the chance for more magnetite to collect, maybe the quiet one will start making noise in the future, maybe never make noise. It could also depend if the bearing gets scored from the magnetite or not. Alot of variables when it comes to water quality and suspended particles.

Dave H.

swellman

@PC7060 - I tried turning down to setting 2. It is continuing to read HI for the GPM and basically max wattage (43 W). I now have a temp difference in the range of around 5 Fahrenheit. So maybe a couple of degrees/slight improvement on the temp differential but really not much...? Is there a concern with dropping it down another speed? @Canucker mentioned there could be a problem with it being too slow?  

The way the boiler/relay/thermostat works is the thermostat calls for heat which turns the pump on which turns the boiler on. Boiler stays on so long as pump is on with the exception of the high limit switch cutting the flame whenever the water gets above ~130 Fahrenheit. 

PC7060

That’s the same situation I had at setting 2. Dropping down to setting 1gave me 4gpm cold / 7-8 gpm at temp. 

Re the minimum flow, earlier I asked what type of boiler you have and from your answer it seems like you have a old cast iron unit. If this if correct, there is no minimum flow rate other than the amount of water you need to circulate to keep the zone warm. 

Mine is a UFT80 Mod Con unit with minimum flow rate of around 1.5-2GPM. 

What the brand and model of your boiler?
I echo the many recommendations to put a Discal DirtMag inline before the pump to protect it from the metal coming off the CI radiators. 

I installed mine right between return lines trunk and the boiler. My pump is located above the boiler out of frame. 

Sorry about the slow response. Work has been keeping me busy. 

HomerJSmith

If you have to pull the Alpha 2 apart to clean it, you can try this. Remove the rotor and use cellophane packing tape to stick to the rotor and pull off any magnetite sticking to the magnets on rotor.

Canucker

PC7060 said:

That’s the same situation I had at setting 2. Dropping down to setting 1gave me 4gpm cold / 7-8 gpm at temp. 

Re the minimum flow, earlier I asked what type of boiler you have and from your answer it seems like you have a old cast iron unit. If this if correct, there is no minimum flow rate other than the amount of water you need to circulate to keep the zone warm. 

Mine is a UFT80 Mod Con unit with minimum flow rate of around 1.5-2GPM. 

What the brand and model of your boiler?
I echo the many recommendations to put a Discal DirtMag inline before the pump to protect it from the metal coming off the CI radiators. 

I installed mine right between return lines trunk and the boiler. My pump is located above the boiler out of frame. 

Sorry about the slow response. Work has been keeping me busy. 

Do we know it's a conventional cast iron boiler? Raypak made one that had cast iron end pieces for its copper tube heat exchanger. If you look up above the burners, you should be able to tell @swellman. If it has tubes, you need a minimum flow rate