Buderus Hydro Air System - Need Help Please!

jrutig

Hi - we recently moved into a house with a Buderus G215 boiler and Logamatic 2107 hydro air system. I’ve spent weeks trying to get the system set up right. Spoke to Buderus tech support. Changed the Logamatic program. Had multiple service techs at the house. I’ve realized what I need is a real expert. Some one who knows Buderus hydro air systems backwards and forwards. Can anyone please recommend a tech?  I’m exhausted and need help. Located in Easton CT. 

EBEBRATT-Ed

Have you called Buderus for a recommendation?

GW

I know that control very well, what’s it’s good at and not good at. Air handler system—-I learned many years ago>>>>not a food fit. Air handlers need higher temperatures. If my momma, brother or daughter bought a home with that set up, I’d trick the control with resistors to simply shut down unless there was a call for heat. Do you have other styles of heating or just air handler/warm air?  

jrutig

yes asked Buderus for a local expert. They recommended a company that hasn’t returned my calls. 

The problem is not the amount of heat. It seems more than capable of keeping the house comfortable. The issue is verifying the overall system set up. There are 5 air handlers each on a zone valve controlled by thermostat. There are 2 grundfos circulators,1 for DHW and 1 for heat controlled by the Logamatic. Based on what I can tell there is a piping circuit for the constant circulation of hot water to the air handler with zone valve locations. There are also several ball valve shut offs along this circuit. When we moved in they were closed and the heating circulator was very noisy when there was no call for heat and zones were closed. Kind of made sense it wasn’t able to move water anywhere. Opening the circuit ball valves solved the noise issue. But with the circuit available it seems like a couple of the zones don’t actually exchange heat when zone is called.  It’s like the water just wants to flow right by. Close the ball valve however and the exchanger gets nice and hot right away on a call for heat. I’m no expert but I’m pretty sure something is wrong here. 

EBEBRATT-Ed

@jrutig

Another option is to check "find a contractor" on this site and post your location. Someone may know someone to recommend

SuperTech

I agree with @GW, you probably would be better off with a simple aquastat. But it sounds like your problem isn't a Buderus problem, an issue with the Logamatic 2107 or even a hydro air issue.  It sounds more like a piping/installation issue. For just a few hydro air zones and a indirect tank it should be fairly simple. Can you post some pictures of the boiler, piping and controls?

HVACNUT

Yes, post some pics please. 
Is there a zone controller for the zone valves? There should be. It definitely shouldn't be wired for constant circulation with hydro air. 
Typically, when heating with circulators, terminal 63 on the 2107 powers 120v to the zone panel, but with a 24v zone panel, I'm not sure how that's done. Terminal 63 is basically for DHW priority. 

GW

edit---OK thought for sure we were having a 'too much fuel' conversation there for a moment.

Seems like most of your problems are piping related (nothing to do with the Buderus system). If your local heating guys can't figure out how to make the water flow and exchange heat, you're in real trouble.

The zone valves should be running through a zone controller (Like Taco ZVC series), and the pump output on that controller has a pump 'end switch'. Just run the 63 terminal (on the 2107) hot leg through that end switch on the taco, then back to the pump. No more 'dead head'

jrutig

First off thank you all for the responses I really appreciate the help and insight. 

Gary you are mostly right. I do have plenty of fuel related efficiency concerns and set up questions but they can’t be sorted unless the piping is understood. That’s why I’m looking for some one local with your expertise. I bet you’d take one look at the set up and know exactly what to do (like the zone controller suggestion). 

It’s very hard to get a picture of the piping but I drew a diagram that might help. 

The little yellow ball valves are causing the confusion at the moment. I leave the one on the right hand side loop open to relieve the circulator. And I have to close one on the left hand side loop to get heat exchanger coils nice and hot when heat is called. 

GW

OK yes, I think I understand, that's a little scary. I'm not there, so I am just blowing some opinion as I type.

When you split the loops like that- and then you have "secondary circuits" coming off of the 'main loops', all on one pump---I can see that being a failure for sure.

The one pump- that will take the path of least resistance. If you have 'zero' heat, then it's probably not 'purged' and the air is blocking the flow of water (heat). But even then, if they are all purged, I can definitely see a lack of flow to one or more (if multiple zones are on).

One at a time, then it should work 100% for whatever zone is on. More than one---gotta flip a coin.

Of you have a cold ahu, then it's not purged.

Purging is is a little funky but probably can be done (I am not there to see all the valves). If you purge, you just need to do so one air handler unit (ahu) at a time. And--be careful you can 'see' the flow of water and don't allow an air bubble to go backyards, into an ahu you just purged. You kinda need 'main loop purges' and you need 'secondary loop purges'. While you're at it, you may been some 'balancing' to keep all 4 ahu's happy, if they all run at the same time.

GW

Also---what noise?? please describe it. Those valve must remain closed

BDR529

Need the temp rise, dump the 2107 and run a Honeywell.

jrutig

Ok I’m glad I’m not going crazy thank you!  The water taking the path of least resistance is exactly what I thought was happening with the ball valves open. The exchangers do get hot (slowly) but most of the hot water just slips by and goes back around. 

The system has been purged and checked up several times while troubleshooting so I’m thinking that’s not an issue for now (water flows quietly and heats things up). 

What do you mean by balancing please?

With all the ball valves closed the circulator (which is constantly on) sounds like it’s struggling. You can hear the motor humming and like a whooshing noise from the pipes. My assumption is the pump is just spinning because with ball valves and zone valves closed, the water is stuck. (Just fyi the old grundfos pump and a brand new Taco pump (lasted 3 weeks) burned out this year so far. There is a new 3 speed grundfos on there now). 

HVACNUT

The circulator must be rewired to only power when a zone valve opens.

STEVEusaPA

If the circulator only runs while a zone valve is opened, then all the ball valves should be closed. There's no reason water will want to go into the air handler loops when it can just zip on by. I'd forget constant circulation and get it wired up correctly. Then you would need some balancing (circuit setters) to get all the flow where you need it.

GW

OK you need to get someone that has some more skills. This is not advanced stuff. I think you're saying you're 'dead heading' the pump when no zones are calling---that's kinda lame. Not rocket science to correct that, but many plumber-heating guys can't deal with control/ wiring, so round and round you go.

Balancing> if all 4 zones are on, the water will simply take the path of least resistance. While that is true 99% of the time (when you have zoning), the other 'longer' zones still get some flow, becasue the circ is pushing and pulling water in all directions possible. The way you drew that out, you're exacerbating the flow issues a lot. You can't keep looping off of loops and expect good flow. To 'balance' simply means to choke some flow on a zone that works well, so the other zones can have a shot at working. 'Globe' style valves are best, but any valve will work (more difficult to fine tune a ball valve, the point of adjustment is very small increments in the vale orientation)

I'm just opining- your system might work if you're 100% sure it's fully purged. But I have a doubt or two.

jrutig

Honestly I would have thought this problem was easier to solve. The techs I’ve had in only seem to know how to carry out a service or replace parts (although now I’m wondering about that as well). 

When I spoke with the Buderus tech he told me the Logamatic runs the circulator continuously until the outdoor sensor triggers warm weather shut down. 

If all the zones are closed and I close the ball valves on the circuits how can dead heading the pump be avoided?  Nothing is wired to the boiler except the circulators so it has no idea what the zone valves, air handlers or thermostats are doing. It just heats and pumps water. I’m wondering if the most cost effective solution might be a grundfos alpha smart pump. To put a zone valve controller in I think I’d need to run new wiring from all the thermostats and zone valves is that correct?

The system does heat the house but I’m sure your right, it’s probably out of balance and getting the job done very inefficiently. I’d love to sort out all the problems but first and foremost I need to find someone local who actually knows how to diagnose and correct things. Easier said than done unfortunately. 

SuperTech

Is there any possibility of correcting the piping? That would be the best solution. All of the air handler supply pipes coming from the boiler in a manifold, then returning to the boiler on another manifold. One circulator for the air handlers, one for the indirect. 

jrutig

I think changing the piping would be very difficult. Some of the air handlers which share a loop are located far from the boiler room. I also wonder why the system was originally designed this way. The house was built in 1989 and I don’t see evidence of cutting corners. Considering the distances the pipes run to the farthest air handlers could the intention have been to keep hot water circulating so when a call for heat came it wouldn’t take time to heat up the coils?

STEVEusaPA

The easiest thing to do is change the control stragegy. The better thing to do is to change the piping.

jrutig

Would replacing my constant circulation pump with this variable speed ecm version be an effective fix?  I understand it might not be 100% ideal but given the constraints might it get me like 80% of the way there?

HVACNUT

From your original post, everything heats fine when the ball valves are closed, but the circulator is noisy when there's no call for heat and the zone valves are closed, due to constant circulation. 
Open the ball valves, and some hydro coils don't heat, but no more noise.
I'm not sure, maybe @GW or someone familiar with the R2107 can correct me if I'm wrong, but I think it will need a single zone relay added. I don't believe the 2107 has an input to control a circulator. 
The 2107 is not an aquastat. It only adjusts its  temperature based on outdoor temperature for heat. It doesn't even know if there's a heat call, hence constant circulation. 
So a separate relay wired like the one below should solve the issue. You (or someone) will need to run a thermostat wire from each zone valve end switch (which I'm sure aren't being used as is) back to RW (TT) on the relay. ZC in the diagram will go to terminal 63 on the 2107. ZR is not used. This way the circulator will only run once a zone valve is open. 
Terminal 63 is basically for DHW priority. If there's a demand from the indirect, then 120v is removed from 63 until the tank satisfies. And I believe there's a 2 hour limit on priority to prevent freezing on the heat side.
Obviously the 2 ball valves splitting the supplies and returns will stay closed.

GW

“Didn’t cut corners” is neither here nor there- you think the builder spent time and energy finding the top-tier hydronics contractor? No, he did not. General Contractors don’t know this stuff at this level of detail. I worked many years for builders. 

hvac guys and boiler (hydronics) guys are rarely good at both. It’s a simple fact. Each of these disciplines take many years to get good at. A decade to be full on pro.

that Alpha circ is great. But the pump has no brain; it’s getting voltage based on the boilers control system(s). An Alpha would be a good band aid. 

It’s simply a poor design; a mis-match in components used. 

No matter what—-to deal with this problem you need the zone valves (zones) to tell the boiler what’s going on. If you stay with 2107— you want to have that pump stop when no zones are calling. If you yank the 2107: Now you need a way to “call on the boiler and move the water”. 

The control system you have now works off of outdoor temperature. The more basic control works off of a thermostat input. Either way, you’re kind of stuck

If it’s impossible to get a small wire(s) from those zone valves back to the boiler, you’re kinda jammed. You “could” simply manually open the zone valves and let all 4 coils heat up. Then the thermostats simply kick on the fan to blow the heat. This will waste some energy (fuel) though. 

I’m curious where the transformer is for the zone valves. Based on that answer- it’s maybe possible to utilize the wire(s) to pull this off 

jrutig

Thank you all again for all the advice I really appreciate it!

The transformers for the zone valves are located on the air handlers. There is an off chance some of the abandoned 1980s home automatically tech left some low voltage wiring I could get back to the boiler room. I’ll do some investigation. 

As for the grundfos alpha circulator, you mention it may be a good band aid. If I understand how the ecm works on this pump as it senses increased resistance it basically slows itself way down. So if all the zones and ball valves were closed (highest resistance) it would power way down. And when zones open and resistance decreases the pump powers back up. I’m wondering with that pump and leaving the ball valves very slightly open if the existing system would operate pretty close to a properly piped and wired system?  

If I can find a way to do it right that’s certainly my preference.  I want an efficient reliable system. But if the band aid gets me 89-90% of the way there without a major retrofit would that make the most sense given the cost / benefit trade off?

SuperTech

The Alpha circulator help avoid the problem of deadheading the circulator because yes, the pump can remain energized and it will start and stop on its own. I would combine that with a couple of relays on the zone valves. Put a relay on one of the zone valves on the left side of your diagram and another on one of the zone valves on the opposite side. Wire the normally closed contacts to give one zone priority over the other one. That's probably the simplest solution. 

GW

I don’t know how well or poorly the Aloha will respond to a dead head 

SuperTech

GW said:

I don’t know how well or poorly the Aloha will respond to a dead head 

They aren't affected by it. I have tested this on my boiler and if all zone valves are closed the Alpha will stop automatically. They sell a version of the Alpha that comes with a plug on it so it can be plugged into a regular 120 volt outlet and left energized. Then the Alpha will modulate based on how many zones open.

jrutig

So it’s sounding like the grundfos alpha might be effective and cost effective fix for my system. 

One question about the alpha variants. I was originally thinking the hard wired version. But now I’m wondering if I used the plug in version instead would it improve that annoying 5-10 minutes where the DHW takes priority and the ahu’s blow lukewarm air?  Or am I pushing my luck with band aids now?

GW

May as well- just unplug after heating season

the chance of running the tank cold will increase a bit, boiler will have less oomph for the tank

but you did say G215 (not a small boiler)- might be goos to go 

jrutig

Ok checking back in to update. I finally convinced my hvac company the set up was wrong. We were able to identify wiring running from each zone valve end switch back to the boiler room. A Grundfos single zone pump control was added. My question is was it wired correctly.

Based on what I understood this was how it should be wired:

However this is how they actually wired it:

Am I wrong or does this eliminate DHW priority and WWSD?  Anything else I should be concerned about?