ECM ciruculator compatible with Lochinvar WH-055??

jch

Lochinvar specs a wet-rotor 3-speed circulator (Grandfos PUM3020) for their WH-055 boiler.  It uses 1/6hp (125W) and runs according to delta-T.



Was wanting to use a newer ECM "smart" circulator to:

- use less electricity, and

- allow constant delta-P (i.e. a flat pump curve) to drive the manifold home-run system I'm building.



Anyone have any suggestions?



Thanks!

.../j

SWEI

Smaller options

Wilo, Grundfos, Xylem, and Taco each sell one model of residential ECM circ, and they  all have curves similar to that of a 008 -- a bit more head on the ecocirc 19-14, a bit more of both head and GPM on the Alpha, but basically intended for the same application.  We have options larger than this in the commercial lines from multiple manufacturers, but the only smaller ECM circ I know of is the ecocirc e-Series (which is available in a variable speed version, but only offers manual control.)  I still use & recommend them, but would be thrilled to see some smaller offerings with onboard logic.

Steamfitter66

What type of Installation are you planning?

Radiant floor , cast iron, or other? new construction or replacement? I like Grundfos and the alpha is a good pump.

jch

Current parameters of system design

Duplicate (shortened) post deleted by original poster.

jch

Current parameters of system design

This is a complete heating retrofit of a 1942-vintage house that has since had its air-sealing and insulation upgraded.



Originally:

1,000 sq ft stucco wood frame house with no insulation in walls, no

insulation on foundation, and R12 insulation in attic.  Heated by

gravity-fed oil-fired boiler (69%) and cast-iron hot water radiators on

main floor.  Basement heated only by standby leakage heat from boiler.



Upgrades:

Two offices built in basement and heated with electric baseboard.  200

sq foot bump-out addition added to main floor kitchen over piers. 500 sq

ft second story developed and heated with electric baseboard.



Have ripped out the old boiler, installed a natural gas feed, and want to entirely get off electric heating while I'm at it. 



Am considering Lochinvar WH-055 gas-fired boiler, feeding directly in to a manifold (no P/S loops). 



**

The main concern I have is in dealing with the small heating zones

(much less than the 10,000 btu/hr minimum firing rate).  I was hoping that a "smart

pump" that maintains constant delta-P (rather than constant delta-T

like Lochinvar's recommended wet rotor circulator) would help make the

system easier to balance.  Am also wondering whether I need a buffer

tank to reduce boiler cycling?





The existing cast-iron

radiators are now oversized (because of the increased insulation and air

tightness) but are almost exactly right if I run them at 120F (which

would also keep the boiler in its condensing range).



Heat loss

calculations for the whole house are 32,000 - 41,000 btu/hr at 26F (our

design temperature here in Victoria BC), depending on whether I insulate

the basement walls or not.



Basement (3 zones?):

- 2 offices,

currently heated by electric baseboard.  Want to switch to radiant

panels.  1 office is used all the time and should therefore be on its

own zone.

- 13,000 - 18,500 btu/h (2,000 for each office) plus a whack for the rest of the uninsulated basement.



Ground floor (6 zones?):

- 5,000 btu/hr for tiled kitchen addition that has an exterior floor (on piers). 25 btu/hr/sq ft.

- 2,000 btu/hr for tile kitchen floor (20 btu/hr/sq ft)

-

Considering installing two rows of Rehau heat plates in each 16" joist

bay on underside of floor with 1/2" PEX.  Have not been able to find

specs on whether I can meet the heat output with 120F water.  

Considering putting it on same zone as kitchen addition?



- 1,000

btu/hr for tile bathroom.  Want to keep floor temp at 80F+ for comfort. 

(20 btu/hr/sq ft).  Considering separate zone with underfloor heat

plates and in-floor heat sensor.



- Two bedrooms (1,800 + 1,900

btu/hr) with existing oversized cast-iron radiators that will meet heat

requirement with 120F water.  One kid likes a warm bedroom at night, the

other likes it cool.  2 more zones?



- Front hall (600 btu/hr)

with no vestibule.  Needs quick recovery when front door kept open

(unfortunately fairly common).  Has cast-iron radiator.  Separate zone?



-

Living room (4,100 btu/hr) plus a leaky open-hearth fireplace that is

usually plugged.  Has two cast-iron radiators.  Separate zone?



= 16,400 btu/hr on main floor.





Upstairs (developed attic) 2 zones?:

-

Office (1,400 btu/hr) that is often heated by just the computers

running in it.  Currently electric baseboard.  Considering radiant panel

on a separate zone.



- Bathroom (1,000 btu/hr) that has electric

in-floor heat, set to maintain a minimum surface temperature of 80F. 

Considering leaving as-is.



- Master Bedroom (3,300 btu/hr) that has electric baseboard.  Considering radiant panel on a separate zone.



= 5,700 btu/hr on upstairs level.





Suggestions??

Weezbo

jch ,

what are you doing in the way of indoor air quality or air exchanges in the offices and home?

do you plan for an erv at this time ?

Steamfitter66

Use TRVs on the cast iron and panel radiators

As they modulate so it can help minimize short cycling. They are also a perfect match to the DP pumps. I like the little Knight and am installing one next week on a 36K heat load.

SWEI

If you can design to a single water termperature

for the majority of the system, you can dispense with the zoning.  TRVs will help in spaces which are subject to intermittent occupancy or overheating from an external source (woodstove, solar gain, cooking, etc.) 

jch

ERV

The house is still leaky enough (4.6 ACH50) that I have no immediate plans for an HRV.



The WH-055 boiler would bring in its own air from outside.



.../j

jch

Not sure about TRVs

While I like the concept of TRVs, I'm not sure I could live with them.



For the past several years, we've run oil-filled plug-in electric radiators instead of running the oil-sucking boiler.  With the oil & electricity prices here in BC, that's saved us over $1,000/year in heating bills....



The problem I've had with those heaters is twofold:

1) The thermostats aren't accurate, probably because they are integral to the heating units and therefore can't sense the true room temperature; and

2) We have to remember to manually turn them on/off every day as we leave the house, return, go to bed, etc.



I suspect that TRVs mounted on radiators/panels would have the same problems.



Comfort and convenience is a big reason for doing this retrofit.  I'd really like to be able to program the thermostats and forget about it.



This house is old-style, i.e. broken up in to many different spaces rather than being open-concept, so the zones are very small heat-wise.  Not sure how well it would work with one big zone and TRVs.

jch

TRV accuracy?

How accurate are TRVs in controlling true air temperature?  The problem we've had with stand-alone electric heaters is that the built-in thermostat ends up physically heated by the heating unit rather than monitoring the true air temperature.



Do you know of any TRVs that are programmable or remote-sensing?

SWEI

TRVs

Do a surprisingly good job of regulating temperature, as long as they are installed properly.  Remote bulb models are available from most if not all manufacturers selling here in the US.  Programmable versions are available in Europe and probably Canada, but (so far) they read only in degrees Celsius.



Setback is usually a fools errand with radiant -- especially when paired with tight ODR control.

jch

How do you accomodate those who like/dislike a cooler bedroom at night?

Thanks -- hadn't thought of that.  So tight ODR control would make for a very long recovery time....



So instead you'd recommend setting up the zones so that all the rooms that need to be cool at night are on one zone?



I've got a son who likes a warm room at night and a daughter who likes it cool in her room at night.



From the user's perspective, how do programmable TRVs compare to programmable wall thermostats operating zone valves?  Do TRVs operate linearly whereas zone valves are all or nothing?

SWEI

TRVs are proportional

unlike common zone valves, which can only turn fully on or fully off.  They pair quite nicely with outdoor reset.  Each radiator on which you install a TRV becomes its own zone -- just remember that a TRV can reduce a radiator's output but not increase it.  If your daughter turns down the valve, her room will be cooler.

jch

TRVs vs Zone valves

My understanding is that TRVs can't "call for heat", so the circulator would have to be running non-stop with delta-T logic controlling the firing of the boiler??

SWEI

Calling for heat

is done by the boiler's ODR settings and the outdoor temperature.  You can install an indoor thermostat, but unless you set it a few degrees above the desired space temp (in effect making a high limit control) it will fight with the ODR.



A pressure-dependent circulator works fabulously with TRVs.  It will turn off whenever the outdoor temp rises above the WWSD setting in the boiler controls.

jch

What if there are radiant floors too?

If the entire system were cast-iron radiators, then this sounds like it would be a fantastic setup.



How would a network of TRV-controlled radiators work in conjunction with a large part of the ground floor (kitchen & bathroom) using underfloor heat loops?  I won't be able to size them exactly and was hoping to use in-floor temperature probes to keep the tiles at least 80F during the cold months...



???

Steamfitter66

The trvs will allow you to combine the 2 with minimal side effects.

Also may allow you to run just 1 water temp. Say your radiators need 120 but the floor needs 130 the TRV will slow the flow of water [and btus] down to were the radiator sees an avg of 120 across the radiator.

SWEI

You can also

put a remote-bulb TRV on a radiant floor.

jch

Main advantage of TRVs over zone valves/thermostats?

Just trying to get my head around the advantage of TRVs over a manifold feeding zone valves and thermostats.



Is the main advantage installation cost?



Or is there another advantage?

Steamfitter66

ease of installation and

modulating control instead of on off. Should see very consistent room temp.

jch

What controls the burner firing?

Looking through the installation instructions for the Lochinvar WH-055, it looks like:

- it recommends a delta-T wet rotor circulator that is controlled by the WH-055; and

- the logic in the WH-055 determines when to fire the burner based on Call for Heat being received from a thermostat.



Because this house is in a place that is subject to wind storms (over 60 mph), how do we control the firing of the WH-055 if we are using Outdoor Reset and TRVs??



Doesn't there need to be an internal temperature monitor *somewhere* to compensate for the varying heat loss load for a given outdoor temperature?

SWEI

Indoor thermostat

set 2-3ºF above the desired space temp will essentially always be calling for heat, unless the room gets too hot from some other source.  If you adjust the ODR curve so that it's comfortable on windy days, it should prevent overheating on non-windy days.



The right answer is indoor feedback paired with outdoor reset, but that requires a thermostat that communicates with the boiler.  Viessmann (and I think Rinnai) offer them but they are not compatible with other manufacturers' boilers.