System upgrade advice

OlGrandad

I'm a homeowner ready to replace our old oil boiler system & plan to do most of the work myself. I've been stalking here for a while plus catching videos with Seigenthaler and Hot Rod to get up to speed, my plan is formulated and I'm looking for input on some final details.

Location is central PA, house is a 1950's brick single story, 2,600 sq/ft with full finished basement, mostly updated dual pane windows, minimal attic insulation and nothing behind the plaster walls but the fiberboard outer layer & air gap to brick.

Unknown size for old boiler - no manufacturer tags of any kind and est 40 yrs old. I'm using Seigenthaler's HDS to help figure things out (and keep track of details) but still looking for suggestions/recommendations. Currently 2 zones but expect to add a garage zone and maybe another zone or two later none of which are part of the heat loss calcs below. HDS says zone flows are 11.5 gpm and 7.6 gpm with current Taco 007 pumps & piping.

Heat loss numbers:
61,290 BTU/hr - calculated from last season's actual oil usage @ 11* design temp
66,232 BTU/hr - HDS manual j calc (11* designtemp) with room by room breakdown

Zone 1
Direct return loop of 181 ft of 1" iron pipe
31,789 BTU/hr heat loss according to HDS
101 ft of 7" baseray @ +/- 220 BTU/hr/ft @ 140* = 22,220 BTU/hr of radiation

Zone 2
Reverse return loop of 147 ft of 1&1/4" iron pipe
34,443 BTU/hr heat loss according to HDS
72 ft of 7" baseray = +/- 220 BTU/hr/ft @ 140* = 15,840 BTU/hr of radiation
Burnham radiator (in wall), 18 sections = guessing 4,000 BTU/hr @ 140*
Living/dining room needs more radiation so probably adding 14ft of 9" baseray to fit curved window walls


Here's what I've purchased so far or will have leftover from old system:

HTP UFT-120W - 120K BTU w/ 10:1 turndown. Overkill but cheap and with my zone loads and buffer tank I'm seeing 5hr run times in HDS so think I'll be ok.
Turbomax 23 - 23 gallon buffer tank/reverse indirect water heater
Grundfos Alpha 2 - circulator for primary loop
(2) Taco 007-F3 pumps - zone pumps from old system
40 feet of 7" baseray previously removed when walls were taken down.

Planned:
Caleffi air/dirt separators
Expansion tank (4.4gal)
Lots of fittings, valves, shut offs etc
20 gallon electric water heater as back up - fed by the Turbomax indirect
4 zone controller - either zone pumps or zone valves depending on your input

I'm not sure I'm using HDS correctly or fully understand what I'm getting so before I order more I have questions such as pipe size for the primary circuit - 1" or 1 1/4" ? Supply & return headers will be 2" iron pipe (less than 2 ft long) but in/out of both boiler and buffer tank are 1 1/4". Planning on 1 1/4" fixtures but they're harder to come by and I don't want to downsize out of convenience if it affects performance. I do have a pro press tool up to 1 1/4" and prefer not to solder but looks like I'll have to mix & match connection types based on available stock.

Next, should I stick with the two 007 zone pumps or use one and add zone valves instead or get 2 more Alpha 2 pumps. Or do something else? Cost is already going beyond budget but I can get a couple more Alpha 2's cheap and am leaning that direction now.

I'm ready for your recommendations and any/all feedback is appreciated.

hot_rod

If you plan on adding two more zones in the future, an Alpha with zone valves would be my choice

Are you using the Turbomax as a buffer and a hydraulic sep?

Have you calculated required SWT at design?

The Turbomax could run at the boiler temperature controlled by ODR then use the electric tank to boost the temperature of the DHW, when the tank temperature is low, based on ODR
There will be times when the tank is only running 130, maybe lower. It may not give you enough DHW at that low tank temperature.

If the load is 65k 1” tube would be adequate from the boiler to the Turbo headers. If future zones take the load up then I would go with 1-1/4,

hot_rod

Idronics 17 has some buffer ideas

If the electric WH is in series, put the mix valve at that tank, as it will store more DHW if it runs up hotter from the Turbo feed

OlGrandad

Thank you Bob, I wasn't sure if the Alpha 2 (15-55) would work as the sole zone pump based on the flow rates HDS was showing me but I trust your input on that. Alpha 2 with zone valves works for me.

In HDS I set water temps at 140* when running calcs but not sure if there is another way or place to calculate required system temp. HDS doesn't have cast iron as a radiation option so I used the closest copper fin option I could find and it shows that at 140* I don't have enough baseboard to fully cover the load at the 11* design temp. But I've done calcs with both current and with the additional radiation I know I can add and I can get pretty close to the 99% numbers.

Yes, Turbomax as buffer/hydraulic separator in a 2-pipe setup since it is single set of in/out ports. Unfortunately space constraints ruled out most larger diameter 3 or 4-pipe tank options. Considered your water heater as buffer tank option btw.

Hard water is taking out our current water heater which prompted the Turbomax option. The new small electric tank will be in series after it and yes, with mixing valve at water heater output. Thnx again to your vids & idronics.

And I'll stick with 1 1/4" pipe then as I'm pretty sure I'll be adding the garage circuit at minimum. The cast iron radiator currently in there is disconnected - I'm guessing it leaked as it was piped direct from zone 2 loop, not on it's own glycol loaded circuit.

Thanks again Bob, I really appreciate your responses and feel comfortable with proceeding.

OlGrandad

With Z series zone valves and the Alpha 2 pump would you recommend balancing valves to equalize the circuits? Does it matter since ODR is controlling system water temp and there won't be night time setback on the t-stats? If both zones are normally be open at the same time won't the pressure differential between circuits send the water on the path of least resistance causing one circuit to cycle more frequently?

If balancing valves are recommended, is the Caleffi 132 valve ok if the minimum is 5gpm? HDS calculated flow rates are 11.5 and 7.6 gpm so if the easier flow circuit is the 7.6 then I'm not sure if a 132 would even come into play much.

hot_rod

OlGrandad said:

With Z series zone valves and the Alpha 2 pump would you recommend balancing valves to equalize the circuits? Does it matter since ODR is controlling system water temp and there won't be night time setback on the t-stats? If both zones are normally be open at the same time won't the pressure differential between circuits send the water on the path of least resistance causing one circuit to cycle more frequently? If balancing valves are recommended, is the Caleffi 132 valve ok if the minimum is 5gpm? HDS calculated flow rates are 11.5 and 7.6 gpm so if the easier flow circuit is the 7.6 then I'm not sure if a 132 would even come into play much.

The balance valves add some fine tuning to the system. With that circulator and zone valves you should be goid to good