New boiler and controls installed as follows:

Solaia boiler Mod SL5125 with Honeywell L7248L aquastat

4 heating zones and one hot water tank zone

StorMore 40 gal tank set at 125 degrees

Taco zone valve 9300-1044

Taco PC 700-2 Boiler reset

1070 Honeywell wireless controls x3 Honeywell hard wired:

Baseboard radiators


Settings on Boiler reset as follows:

Boiler start:80

Outdoor start: 70

Boiler design (as per manufacturer) 130

Outdoor design: 0 (I live in Connecticut)

Boiler minimum: 80

Differential: Auto

WWSD: 68


Honeywell boiler control Settings:

HIGH LIMIT: 180

tt Local Thermostat Status: off

ttE Envirocom Thermostat status: off

ELL External Low limit: OFF

duu ZR configured as domestic hot water request: off

bSP Boiler setpoint: 180

dhc DWH Module connected: no

One zone to unused bedrooms kept at 55 when not in use. When needed it takes 5-7 hours to heat these rooms and this seems long.

Regardless of outdoor temp, furnace starts every 4-5 min and cycles from 160-180 then off 5-10 minutes depending on how many zones are calling for heat and then recycles.

When hot water temp drops from use, boiler goes on even though the boiler temp is 160 or above.

I do not think these settings are optimizing my fuel usage and would like your input. Any help you could give would be greatly appreciated.

Should burner go on when hot water tank falls below 125 degrees even if boiler water temp is between 160-188?

 

teezee, there is nothing wrong with hitting the RETURN key every now and then to make a post more 'readable'. I heavily edited your post to add the missing 'white space' ... I couldn't make any sense of it until I did that.

What is this? a 'part number' of a Taco ZVC panel? If so, what is the MODEL NUMBER of the panel?

I haven't looked at the settings for the 7248 in a while... what does this mean?

Is this just saying that at the time you looked at it, there was no call for heat and the TT terminals were 'open' ?

What do you have wired to the T T terminals of the 7248 ?

 

Didn't know how much room i had for the question so i tried to conserve space - much better expanded - thanks


Taco 6 zone zvc 406 exp


Yes, when any zone calls for heat it says "on"

it is wired to the prestige thx9000 hardwired thermostat. The other 3 thermostats are wireless focuspro th6320r

 

Why are not your thermostats wired to the ZVC panel, and the ZVC panel running the boiler?

 

Maybe a better question is: How do you have the ZVC panel wired to the 7248 ?

 

This is going to get you into trouble.

First, from the PC700 instruction sheet:
And next from the Solaia boiler install manual:
You had better rethink that setting!

 

You want to set BOIL MIN for 130F. Maybe 120 but see how it goes at 130 for a week or two. For oil-fired boilers, condensation becomes an issue for return water temperatures below about 115F. You want to avoid that.

You should also consider adding a bypass or a thermostatic mixing valve to keep the boiler return temp above condensing, but also allow lower water temperatures in the distribution system. Options for that approach are described here:
Bypass_Piping_Explaination

If you do a bypass, then the BOIL MIN can be lowered.

 

see above note on same topic

 

have changed setting to 120 which Solaia says is OK. There is a bypass to prevent cold water from entering boiler.

 

Wireless thermostats are connected to the ZVC panel and then out of the ZVC to the 7248 along with the hard wired thermostat which are all connected to the tt terminal on the 7248.

 

What you are saying sounds as if you have the ZVC AND a thermostat connected to T T on the 7248... why?

You called them?

Must understand that the 120 setting is the SUPPLY temp, and the RETURN water will typically be at least 20 degrees colder than that, meaning that your return water will range as low as 100 with a 120 supply.

Where is the bypass located in the piping... BOILER bypass? or SYSTEM bypass?

Solaia says 120 is OK, .... hmmmmm... I don't know about that. but, it's your boiler!

 

Is it possible to provide a diagram of how you have the system wired?

 

teezee,
Take their advice on the temp setting.

I destroyed my old boiler (condensation) by not watching return water temp!

 

Boiler temp never falls below 160 before burner is turned on to reach 180 and then shuts off. Bypass is from supply side near boiler to return from all zones. It is located beyond circulator pump which is on supply side. Really have no way of measuring the return temp as it goes into the boiler.

All 4 thermostats go through the zone panel and then to tt.

Wiring as on: Instruction Sheet for Taco PC700-2 Boiler Reset Control (pdf)
Application Guide for Taco PC700 Outdoor Boiler Reset Control (pdf) from Taco controls site.