Hydrolevel 3250+ settings

Rickoo

Background: This past summer we installed a Mitsubishi hyper heat, heat pump multi zone system and until recently we’ve been using it to heat the house. Around the same time, we also installed an indirect water heater off our oil fired Peerless boiler. Our system has two fin tube zones and a unit heater in the basement. All on separate zones with their own circulators. A Hydro level 3250+ (among some other changes) were also installed.

Now with colder temps here to stay for a while, and not convinced the heat pump will actually be more economical with temps in the teens, I want to again use the boiler as a primary heat source.

So, I’m starting to play with some of the settings to try and dial the Hydrolevel in as best I can. The boiler previously had a tankless coil which was removed when the indirect was installed with the plan of now running the boiler cold start. When installed, we set the low limit off, high limit at 170 and the economy dial at 2. Worked fine all summer at keeping the indirect hot.

The unit heater is only used when I want to spend the day in my shop, so that’s typically off. We set the two (first and second floor) thermostats to set back to 63 when we go to bed and turn up to 68 an hour before we get up.

These settings just aren’t enough to heat the house. (At least fast enough.) The temperature in the house this morning only rose 2 degrees in 4 hours. I’m not sure if it’s because the whole house (and its contents) are at 63 and it’s taking time to overcome that, or if the water just isn’t hot enough in the boiler. (or a combination of both) I took a shower when I got up and with the indirect on priority, the recovery took away from heating for roughly 45 mins or so.

So, my question is, what’s the best strategy to dial the hydro level in to the best mix between economy and functionality? I just elevated the high limit to 180 and set the economy dial to Lo to see what happens. Does this make sense? Any other suggestions?

Thanks!

Robert O'Brien

The economy feature uses a time and temperature algorithm, you can also program a fixed differential. I'd try where you are and then move up dial until you aren't happy with performance.

DJD775

How did your system react to the temperature setback before you had the Hydrolevel installed?
HW priority might not be necessary based on your hot water needs.

Rickoo

DJD775 said:

How did your system react to the temperature setback before you had the Hydrolevel installed?
HW priority might not be necessary based on your hot water needs.

Honestly, as I recall, the house heated back up fairly quickly. Enough so, where I don't remember being bothered enough to look into why it was taking so long. With the tankless coil, we had the high limit at 180 and low limit at 160.

DJD775

Let me start by saying I'm not a pro but I've used several of these controls. The good news is that your aquastat can be setup like your like your old aquastat if absolutely necessary. I would start by trying to lower the economy setting incrementally to see if any of the lower settings suit your needs. As Robert O'Brien mentioned above you can shut off the economy feature and run a fixed differential of 10-30 degrees. This can be useful if you boiler has a tendency to short cycle.

EBEBRATT-Ed

@Rickoo

@EdTheHeaterMan has the fix I think your looking for on this site.

EdTheHeaterMan

Set the economy to zero on the Hydrostat. That will get you the 180° water all the time for heat. After the real cold weather is gone, set it back to #2

If you want to do this automatically without loosing the economy feature there is a fix using a 2 stage thermostat to trick the Hydrostat to go the the 180° temperature for DHW heating. but you need a relay to put the DHW priority pump to the CH pump during the recovery time. How this will mess with the indirect has not been solved yet because the 2 people with your problem did not use DHW from the boiler. here is the fix for no DHW

https://forum.heatinghelp.com/discussion/comment/1783724#Comment_1783724

If you are interested, I can try to make that diagram for you. I need to know what zone valves/circulator/relay panel you are using for the zones and how it is connected to the Hydrostat. And what model Hydrostat you have

Rickoo

Thanks @EdTheHeaterMan. Your solution to re-set the economy in warmer weather sounds easy enough. I'll take that approach and study your fix to determine if it's worth the effort for me. Might take you up on the diagram offer in the future.

When you say "set the economy to zero", Do you mean "off" or "Lo"? Levels go from off, to Lo, 1, 2, 3, 4, 5, Hi.

EdTheHeaterMan

Yes. Off in your case. every manufacturer s just a little different.

HVACNUT

When the zones aren't making temperature, I would watch the Hydrostat to see at what temperature it actually shuts off the burner. Assuming the Elecro well is fully seated. Compare the temperature to the tridicator temperature. Its fairly new so it should be correct. Maybe turn down the temperature on the indirect while doing this. You might need to lower the economy setting to 1 or Lo.
I have seen this in the past so check it. Upper right hand corner, jumper B. If the jumper is there, remove it. It prevents the boiler from going over 140°.

Rickoo

Thanks. The economy setting is OFF. Hi Limit set at 180 as suggested by @EdTheHeaterMan.

System still seems to be struggling to hold the thermostat setpoint. Didn't check temps of my baseboards, but they all seem pretty hot.

Burner fires at 170 and shuts off at 180. Boiler temp rises to around 195 before starting to drop. These temps are from the Hydrolevel. Interesting that the tridicator is consistently reading 15-20 degrees below the Hydrolevel. I noticed this when we first ran the boiler and assumed the tridicator was wrong. It's about 24 years old. Temp. probe seems fully inserted into the electro-well.

I have a small thermal imager and the temps taken at the supply piping just out of the boiler look fairly close to the hydrolevel. Return temp taken at the return just outside the boiler is around 140. About 40 degrees lower than the supply. Since turning economy off and setting hi limit at 180, boiler has been running for about 5 hours straight to reach and hold 68.

Outdoor temp has been in the low 20s all day. Cold but not really frigid for sure.

Never had issues maintaining 68 with the old aquastat. Not really sure what to make of this.

DJD775

Possibly under pumped? Were any of the circulators replaced during the install or settings changed on the existing units?

Rickoo

Same Taco 007 circulator. It's 24 years old but has always performed perfectly. 

RollCNY

I have the 3200+ (natural gas) and it would do that same 10° differential and tons of short cycling. You can set the differential wider, it is setting 9. I also saw the same kind of spread between reported temp by the hydrostat and actual, so I set mine with a 190° top and 30° differential. It will still coast up to a reported 198°, but my actuals at pipe at between 180 & 182

HVACNUT

Make sure the sensor is fully inserted in the well. Feel it bottom out.
Are you sure there's enough emitters?
The old aquastat wasn't set to 200°?

Rickoo

Plenty of emitters. The house is 24 years old and never had any issues. Old honeywell aquastat was definitely 180/160.

Not really sure what would be considered short cycling. How long of a burner run time and off time between cycles would be considered good?

Will watch it some more today and report back. Thanks everyone!

RollCNY

Sorry to introduce the short cycling comment, that was specific to me and that 10° differential. The manual for the control makes it look like differential is automatically set, and it is with the Econ feature, but not otherwise.

I do the same 5° set back at night, and have similar set up to you (same zones + indirect) but I'm one pump and zone valves. Ed's comment on turning off econ in coldest weather has worked for me.

As to your problem, I would think that 40° drop is what you need to focus on now. I would make sure first that your measurements are accurate (I bought a $30 Amazon four channel temperature meter w/probes). Since you are zoned with circulators, and the system always worked in the past, I wouldn't think you're under pumped.

You said that they added the indirect tank at the same time they added the Mitsubishi Hyper heat. Any chance they didn't properly bleed the other zones after that install? You said this is the first you've really run the full system. Go one zone at a time, and see if it is only one zone that has the big drop.

Rickoo

No problem @RollCNY. Thanks for your thoughts.

The Hi limit differential can be adjusted with Economy off. Selectable from 10, 20 and 30 degrees. It defaults at 10 and that's where I left it.

Looks like I'm getting approximately 30 degree drop between supply and return piping at boiler. Not sure if this is what I should expect?

I'm getting zero noise from the piping, and the baseboards are pretty warm. Having said that, could air still be in the zone somehow?


Here's some info I've gathered today.

Today's high was around 20, Low teens overnight last night. The sun was shining with little wind.

Thermostat was at set at 64 all night. Auto set forward to 68 at 6:00am. After not reaching the set point around 9:30 this morning I raised the boiler Hi limit from 180 to 185. Within a few hours, it was 68. Thermostat was satisfied and zone turned off. Room with the thermostat faces south west and gets the sun mid day. I'm thinking this was a contributing factor.

Thermostat has been on 68 all day and has called for heat and been satisfied several times. Around 3:15 pm (four hours ago), zone came on when the room temp hit 167. Temp. rose to 168 on the thermostat but it hasn't been satisfied yet. I imagine it's not quite enough to satisfy the call. Outside temp is now 16.

At 175, my burner fires for 2 minutes, reaches 185 and shuts off. For the next 2-3 minutes, temp. in boiler rises to 202 before starting the drop to 175 over 7-8 minutes. Burner fires again.

Do these cycle times seem normal?

I'm wondering if I should raise the Hi limit to 190. Is there any concern that the temp will now likely drift up to 206-207 before dropping?

How high can you safely set the Hi limit? I've seen references to 200 degrees which my temp would surely drift up over the boiling point wouldn't it?

The old Honeywell L8124 was set at 160/180 with the tankless coil. Never remember having issues like this, but honestly if I wasn't monitoring this, I'd be warm, comfortable and happy without maybe realizing the zone was running hours on end to maintain 68. Could the high limit have actually been higher than 180 on the old unit? How accurate were these? Was definitely set at 180.

Thanks for the help!

Rickoo

Yes, new Electro-well was installed when the tankless was removed. Baseboards are all quiet as a mouse and warm. Vents are open and seem to be working fine. Pretty sure it isn't an air problem. Have the economy turned off with high limit at 190 now. Temp. comes up a bit faster now. Going to live with it for a while and see how it goes.

Thanks everyone!

EBEBRATT-Ed

@Rickoo

I would leave the HL at 190. It will only get that high if it needs to. Don't forget the system has 15 psi in it there is no danger of boiling even if you went to 210 it would not boil.

Make sure the baseboards are clean and not obstructed. Limit the night set backs when it is cold