boiler controls

Reply

  #1  
Old 12-22-10, 06:22 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
boiler controls

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?
 

Last edited by NJT; 12-22-10 at 04:39 PM.
Sponsored Links
  #2  
Old 12-22-10, 04:36 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
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.

Taco zone valve 9300-1044
What is this? a 'part number' of a Taco ZVC panel? If so, what is the MODEL NUMBER of the panel?

tt Local Thermostat Status: off
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 ?
 

Last edited by NJT; 12-22-10 at 08:56 PM.
  #3  
Old 12-23-10, 11:11 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Originally Posted by nj trooper View Post
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.
Didn't know how much room i had for the question so i tried to conserve space - much better expanded - thanks


what is this? A 'part number' of a taco zvc panel? If so, what is the model number of the panel?
Taco 6 zone zvc 406 exp


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

what do you have wired to the t t terminals of the 7248 ?
it is wired to the prestige thx9000 hardwired thermostat. The other 3 thermostats are wireless focuspro th6320r
 

Last edited by NJT; 12-23-10 at 01:44 PM.
  #4  
Old 12-23-10, 01:56 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Why are not your thermostats wired to the ZVC panel, and the ZVC panel running the boiler?
 
  #5  
Old 12-23-10, 03:24 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Maybe a better question is: How do you have the ZVC panel wired to the 7248 ?
 
  #6  
Old 12-23-10, 03:39 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Boiler minimum: 80
This is going to get you into trouble.

First, from the PC700 instruction sheet:
Boiler Minimum Supply Temperature (BOIL MIN)

Most boilers require a minimum operating temperature to prevent corrosion from flue gas condensation. The minimum boiler setting should be programmed to the lowest supply water temperature at which the boiler can operate without causing the boiler flue gases to condense. Consult the boiler manufacturer for recommended minimum boiler supply temperatures. Some typical settings are as follows:

Cast iron boiler .................. 135 to 160F (57 to 71C)
And next from the Solaia boiler install manual:
The Solaia boiler is a highly efficient low mass boiler in which care must be taken to ensure that high volumes of low temperature water are not introduced into the boiler. Operating at return water temperatures below 130F for extended periods of time will allow for the accumulation of condensation, scale and increased soot formation in the boiler. Corrosion and eventual heat exchanger failure will result.
You had better rethink that setting!
 
  #7  
Old 12-23-10, 07:53 PM
Member
Join Date: Nov 2005
Location: USA
Posts: 2,459
Received 0 Votes on 0 Posts
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.
 
  #8  
Old 12-24-10, 07:29 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
see above note on same topic
 
  #9  
Old 12-24-10, 07:38 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
have changed setting to 120 which Solaia says is OK. There is a bypass to prevent cold water from entering boiler.
 
  #10  
Old 12-24-10, 07:54 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
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.
 
  #11  
Old 12-24-10, 08:02 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
What you are saying sounds as if you have the ZVC AND a thermostat connected to T T on the 7248... why?

120 which Solaia says is OK
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!
 
  #12  
Old 12-24-10, 08:04 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Is it possible to provide a diagram of how you have the system wired?
 
  #13  
Old 12-24-10, 08:15 AM
Member
Join Date: Nov 2010
Location: USA
Posts: 123
Received 0 Votes on 0 Posts
teezee,
Take their advice on the temp setting.

I destroyed my old boiler (condensation) by not watching return water temp!
 
  #14  
Old 12-27-10, 06:04 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
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.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: