HTP 80W with TurboMax 24, adding (ECM) pumps + zone valves

mtnheat

permit granted for the 2 story 2064 sq' CO mountain residence at 8000'. proposed replacement boiler for NTI T-150 is HTP-80W to power (2) zones, and TurboMax 24 (12 gpm flow). Lower level zone has 47' of fin tube baseboard, upper floor has 57' baseboard. contractor prefers grundfos pumps BUT has not installed their ECM pumps. the suggested Grundfos Alpha 15-55 F/LC would be replacing the (2) existing Taco 007 and the Taco 0010 looks to be replaced. suggestions. the existing ZVs are Honeywell but open for suggestions. there will be an outdoor reset which hopefully will integrate with the pumps. it's been a struggle to get to this point. objective is low energy, low maintenance system for this retrofit...

Leon82

If you plan to dial in the outdoor reset ,resulting in longer burn times, it will be a good idea for the ecm pumps.

The only thing with the alpha is it has a plug on the end if I recall and is powered all the time so it remembers what it has learned.

mtnheat

thanks Leon82 most likely if it's the alpha we'd go the hardwire route. with 3/4 supply /return pipe, seems 4 gpm flow is preferred. on the HTP, at 3.8 gpm it's a 40 delta T. Taco indicates that max flow on 3/4 pipe is 6.5 gpm which is about a 25 delta T on the HTP. still figuring....

mtnheat

hey Hatteras: the DT flow rate and head are from the HTP manual: http://www.htproducts.com/literature/lp-542.pdf pg.35. a 20 DT has a flow rate of 7.6 gpm with a head of 3.1'. a 40 delta T with 3/4 pipe has a 3.8 gpm flow and 1.2' head. i'm trying to fit a proper ecm pump for the zones (which are projected to have ZVs) and a preferably another ecm pump to the turbo max which has a max flow of 12 gpm. thanks... stumped at the moment . appreciate the input

Paul48

You mean that chart that shows a minimum pipe size of 1" for that boiler? You have to be able to unload that temperature rise to the system. That's what Hatteras was referring to. There's no sense in pumping your primary for a 40 DT, when the secondary can only dump 20 DT, at best.

Gman66

Comments from a HVAC junior hobbyist. so take them for what they are worth. With 104' of BB you are looking at max radiation of 57K or so. Split into the two zones you need 3.1 gal into one zone and 2.7 gal into the other while maintaining 20* DT. Those flows into 3/4" copper should be well within the Alpha's capability (12 ft head at 6 gal) assuming no crazy lengths or other issues. This assumes you are using the Alpha as the system pump in Primary/Secondary arrangement, the system pump won't see the pressure drop across the boiler. If you do direct piping you need to look at the added pressure drop of the boiler but I suspect the Alpha would still be OK, the boiler drop looks like just over 2 ft head @ 6 gal. One other thing, the HTP manual requires 1" near boiler piping but your posts suggest 3/4", did you really mean to have 3/4" near boiler piping?

Paul48

I really don't understand the use of a DP circ, unless your only concerns are that the circ pump under all conditions, at the greatest electrical efficiency. How does that translate into system efficiency, and how do you know it will maintain the DT you've designed for?

NY_Rob

Here's what I have observed on my system with a HTP UFT-80W and Grundfos Alpha in "constant pressure mode/speed II" on a space heating call:

1 zone valve open: 2gpm/20watts
2 zone valves open: 4gpm/26 watts
3 zone valves open: 6gpm/34 watts

I understand and agree the the Alpha's GPM/flow rate readings may not be extremely accurate, but they're good for comparison between zones.

mtnheat

Gman66: this is a retrofit. the existing near boiler piping is 1.25" with a Taco 0010 along the supply line to a T for the turbomax 24 with a Taco 007 and another T with a Taco 007 that feeds the zones with 3/4"... the existing ZVs are honeywell on the return.

mtnheat

NY_Rob: thanks...which Grundfos Alpha, the 15-55 ?

NY_Rob

mtnheat said:

NY_Rob: thanks...which Grundfos Alpha, the 15-55 ?

Yes, the Grundfos ALPHA 15-55F.

mtnheat

Hatterasguy: it's been a struggle to get to this point, contractors wanting to do a like-size replacement of the T-150. no one of their own accord went < a 110. utilizing usage data a 99% design day requires 38,000 BTUH. yep, the 80W is too big BUT it also powers the TurboMax and has a 10:1 turn down. could i get away with 55,000BTU boiler after de-rating 17% to 20% for altitude. maybe but not sure who would install it up here. pumps to interact with the boiler is the objective at this point. i'm a novice so peddling as fast as i can given incremental learning.

mtnheat

NY_Rob: is your UFT P/S or direct ? did you go with a grundfos for your SuperStor, think i remember you installing a SS30 ? if so, which one... thanks in advance...

NY_Rob

^ I'm piped direct with the Alpha- three zones on zone valves.
I used the Grundfos 3-speed UPS15-58FRC on the SS Ultra 30 indirect. I keep it on speed II. All near boiler piping 1".

mtnheat

if i go with the Grundfos Alpha 15-55F as the "boiler" pump,(NY_Rob has the same boiler HTP UFT80W but with direct piping and uses the Alpha) since the existing piping is primary/secondary with zone valves, what is the appropriate "circulator" pump ? using the System Syzer app, the longest loop flowing at 4 gpm would have a head of 11.67' (includes a 50% buffer). the supplier here fumed at the contractor when i requested (if possible) three ECM pumps, boiler, circulator, DHW. i'm on my own since trying to get this done. thanks

NY_Rob

The DP Alpha is for the CH/system (space heating) loop where the head value changes as zones open and close.

For the boiler loop you can use a single speed pump (or a 3-speed pump permanently set on one speed) because the head in the boiler loop will remain fairly constant. Well, technically you could use the Alpha for the boiler loop- you would just keep in fixed speed mode .. but it seems like a waste to use the expensive Alpha like that. Taco now makes a ECM 007 pump- check the pump curve- that may be a good boiler loop pump if the head calculations work.


On my system- the Alpha is on the CH (space heating) loop... cause that's the only loop I have- I'm piped direct.

mtnheat

NY_Rob...many thanks...any reason you didn't go with the Taco 007e on your DHW instead of the 15-58FRC?

NY_Rob

The DHW indirect pump doesn't run often, so I probably wouldn't ever save enough on electricity to make up for it's added cost over a standard pump. IIRC the 3-speed Grundfos was $90 when I got it and the 007E is almost $140.

In contrast, the space heating circulator can run 20+ hrs/day on a mod con- that's where you'll save using a ECM pump.

Leon82

I have a viridian 1816 for my boiler pump.it can be adjusted with a dial instead of 4 fixed speads. They call it infinitely adjustable but you can't be that precise with a screwdriver