Where else?

The baths of Nam Rong, Phetchabun

Phetchabun
Phetchabun province is not really well-known by foreign tourists, for instance the Lonely Planet has failed to include it at all!
That seems to be not so fair, in general it's a quiet, laid-back part of the country, fringed with some seriously beautiful mountains. Take an example of Tat Mok / Song Nang waterfalls. Elsewhere there is the historic park of Si Thep.
And of course some hot springs.

Besides Phu Toei 'hot' spring, Thailand Energy and Environment Network (TEEN) list a number of other hot springs in Phetchabun province, totallying 5, whereas Ramingwong et al. (1990) mention 4:

'The surface temperatures range from 35 to 47 C. and the discharges are generally small'.

Phu Kham hot spring
Despite traveling through the town of Phu Kham (or Pukham) there was not much evidence of a hot spring despite the TEEN listing. However this Thai language website begs to differ and translated it reports:

'This hot spring. Temperatures around 45-50 degrees Celsius does not smell of sulfur. Now being updated to a water supply system. In winter the village is taking a hot shower. Loosen the winter very well. Villagers believed that This is a hot spring wells from the holy fire.
...
Travelling by car
Si Thep from the Highway 21 straight through the intersection District Wichienburee Ban Phu Kham. Turn left and go 50 meters to the small junction. Turn right to the Thong Chai Wat Si. Will see a fountain'.

Wangkhasm hot spring
Despite TEEN listing no less than 2 hot springs (well, temperatures above 30C) in this village, they are the only reference. Could also be Wang K(h)am, though this also has no leads.

Nam Ron (Phetchabun) hot spring
Nam Ron translates as hot water and is an often used name in Thailand for a village with a hot spring. To distinguish itself Phetchabun is added, this village falling administratively under the provincial capital district.

TEEN notes it having waters with 50C, which would make it a hot spring.

The village is located on the crossroads of road 2385 and 2275, blink and you will miss it. There's a very small market and a bridge. On the west crossroads side of the bridge, there are two houses directly next to the stream. The back one has a large Welcome sign and is the hot spring.

However when I visited the facilities they were open despite there not being a soul around. Directly behind the entrance were about 7-8 bathrooms each with it's own tub.
A certificate was displayed concerning the presumed mineral quality of the waters (see photo below). Presumed, as the list contains no reference other than pH and chloride.

I nosed around but couldn't find anything that would help ascertain where or how there is a hot spring here, though locals distinctly pointed to this as being the place for a soak.

Additional info from Ellis (2011):

'In 1999 Dean Smart found several small hot springs in the river bank around the bridge in Ban Nam Ron. The water is very hot, but no holes were visible due to the muddy river water'.

Btw, not so far away (national park entrance @ 10 km) are the delicious waterfalls of Song Nang and Tat Mok in the Tat Mok National Park. Oh, I see I have already mentioned them ...


Nam Ron (Wichian Buri) hot spring?
Not on the TEEN list is another Nam Ron village.

Independently I went all the way to this Nam Ron village, 18 km of potholes east of Wichian Buri only to discover that the name had nothing to do with there actually being a spring despite Nam Ron translating as hot water. Huh?

Notes
Ellis, M. (2011) The Caves of Phetchabun. Takobi, Lom Sak, Phetchabun, Thailand.
Ramingwong, T., F. Suvagondha, W. Uttamo, S. Lerdthusnee, K. Wattananikorn, L. Jurasai, & C. Singhasenee (1990) Geothermal pre-feasibility study in the Phetchabun area of northern Thailand. Nippon Chinetsu Gakkaishi (Japan); 12: No. 3, 229-237 (25 Jul 1990).